Provided by: ncrack_0.7+debian-4_amd64 
NAME
ncrack - Network authentication cracking tool
SYNOPSIS
ncrack [Options] {target specification}
DESCRIPTION
Ncrack is an open source tool for network authentication cracking. It was designed for
high-speed parallel cracking using a dynamic engine that can adapt to different network
situations. Ncrack can also be extensively fine-tuned for special cases, though the
default parameters are generic enough to cover almost every situation. It is built on a
modular architecture that allows for easy extension to support additional protocols.
Ncrack is designed for companies and security professionals to audit large networks for
default or weak passwords in a rapid and reliable way. It can also be used to conduct
fairly sophisticated and intensive brute force attacks against individual services.
Warning
Ncrack is a project started in the Summer of 2009. While it is already useful for some
purposes, it is still unfinished, beta quality software. You can help out by testing
it and reporting any problems as described in the section called “BUGS”.
The output from Ncrack is a list of found credentials, if any, for each of the targets
specified. Ncrack can also print an interactive status report of progress so far and
possibly additional debugging information that can help track problems, if the user
selected that option.
A typical Ncrack scan is shown in Example 1. The only Ncrack arguments used in this
example are the two target IP addresses along with the the corresponding ports for each of
them. The two example ports 21 and 22 are automatically resolved to the default services
listening on them: ftp and ssh.
Example 1. A representative Ncrack scan
$ ncrack 10.0.0.130:21 192.168.1.2:22
Starting Ncrack 0.6 ( http://ncrack.org ) at 2016-01-03 22:10 EEST
Discovered credentials for ftp on 10.0.0.130 21/tcp:
10.0.0.130 21/tcp ftp: admin hello1
Discovered credentials for ssh on 192.168.1.2 22/tcp:
192.168.1.2 22/tcp ssh: guest 12345
192.168.1.2 22/tcp ssh: admin money$
Ncrack done: 2 services scanned in 156.03 seconds.
Ncrack finished.
The latest version of Ncrack can be obtained from http://nmap.org/ncrack. The latest
version of this man page is available at http://nmap.org/ncrack/man.html .
OPTIONS SUMMARY
This options summary is printed when Ncrack is run with no arguments. It helps people
remember the most common options, but is no substitute for the in-depth documentation in
the rest of this manual.
Ncrack 0.7 ( http://ncrack.org )
Usage: ncrack [Options] {target and service specification}
TARGET SPECIFICATION:
Can pass hostnames, IP addresses, networks, etc.
Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.0-255.1-254
-iX <inputfilename>: Input from Nmap´s -oX XML output format
-iN <inputfilename>: Input from Nmap´s -oN Normal output format
-iL <inputfilename>: Input from list of hosts/networks
--exclude <host1[,host2][,host3],...>: Exclude hosts/networks
--excludefile <exclude_file>: Exclude list from file
SERVICE SPECIFICATION:
Can pass target specific services in <service>://target (standard) notation or
using -p which will be applied to all hosts in non-standard notation.
Service arguments can be specified to be host-specific, type of service-specific
(-m) or global (-g). Ex: ssh://10.0.0.10,at=10,cl=30 -m ssh:at=50 -g cd=3000
Ex2: ncrack -p ssh,ftp:3500,25 10.0.0.10 scanme.nmap.org google.com:80,ssl
-p <service-list>: services will be applied to all non-standard notation hosts
-m <service>:<options>: options will be applied to all services of this type
-g <options>: options will be applied to every service globally
Misc options:
ssl: enable SSL over this service
path <name>: used in modules like HTTP (´=´ needs escaping if used)
db <name>: used in modules like MongoDB to specify the database
domain <name>: used in modules like WinRM to specify the domain
TIMING AND PERFORMANCE:
Options which take <time> are in seconds, unless you append ´ms´
(milliseconds), ´m´ (minutes), or ´h´ (hours) to the value (e.g. 30m).
Service-specific options:
cl (min connection limit): minimum number of concurrent parallel connections
CL (max connection limit): maximum number of concurrent parallel connections
at (authentication tries): authentication attempts per connection
cd (connection delay): delay <time> between each connection initiation
cr (connection retries): caps number of service connection attempts
to (time-out): maximum cracking <time> for service, regardless of success so far
-T<0-5>: Set timing template (higher is faster)
--connection-limit <number>: threshold for total concurrent connections
--stealthy-linear: try credentials using only one connection against each specified host
until you hit the same host again. Overrides all other timing options.
AUTHENTICATION:
-U <filename>: username file
-P <filename>: password file
--user <username_list>: comma-separated username list
--pass <password_list>: comma-separated password list
--passwords-first: Iterate password list for each username. Default is opposite.
--pairwise: Choose usernames and passwords in pairs.
OUTPUT:
-oN/-oX <file>: Output scan in normal and XML format, respectively, to the given filename.
-oA <basename>: Output in the two major formats at once
-v: Increase verbosity level (use twice or more for greater effect)
-d[level]: Set or increase debugging level (Up to 10 is meaningful)
--nsock-trace <level>: Set nsock trace level (Valid range: 0 - 10)
--log-errors: Log errors/warnings to the normal-format output file
--append-output: Append to rather than clobber specified output files
MISC:
--resume <file>: Continue previously saved session
--save <file>: Save restoration file with specific filename
-f: quit cracking service after one found credential
-6: Enable IPv6 cracking
-sL or --list: only list hosts and services
--datadir <dirname>: Specify custom Ncrack data file location
--proxy <type://proxy:port>: Make connections via socks4, 4a, http.
-V: Print version number
-h: Print this help summary page.
MODULES:
SSH, RDP, FTP, Telnet, HTTP(S), Wordpress, POP3(S), IMAP, CVS, SMB, VNC, SIP, Redis, PostgreSQL, MQTT, MySQL, MSSQL, MongoDB, Cassandra, WinRM, OWA, DICOM
EXAMPLES:
ncrack -v --user root localhost:22
ncrack -v -T5 https://192.168.0.1
ncrack -v -iX ~/nmap.xml -g CL=5,to=1h
SEE THE MAN PAGE (http://nmap.org/ncrack/man.html) FOR MORE OPTIONS AND EXAMPLES
TARGET SPECIFICATION
Everything on the Ncrack command-line that isn´t an option (or an option argument) is
treated as a target host specification. The simplest case is to specify a target IP
address or a hostname. Note, that you also need to specify a service to crack for the
selected targets. Ncrack is very flexible in host/service specification. While hostnames
and IP addresses can be defined with the flexibility that you are probably used to from
Nmap, services along with service-specific options have a unique specification style that
enables a combination of features to be taken advantage of.
Sometimes you wish to crack a whole network of adjacent hosts. For this, Ncrack supports
CIDR-style addressing. You can append /numbits to an IPv4 address or hostname and Ncrack
will try to crack every IP address for which the first numbits are the same as for the
reference IP or hostname given. For example, 192.168.10.0/24 would send probes to the 256
hosts between 192.168.10.0 11000000 10101000 00001010 00000000) and 192.168.10.255
(binary: 11000000 10101000 00001010 11111111), inclusive. 192.168.10.40/24 would crack
exactly the same targets. Given that the host scanme.nmap.org is at the IP address
64.13.134.52, the specification scanme.nmap.org/16 would send probes to the 65,536 IP
addresses between 64.13.0.0 and 64.13.255.255. The smallest allowed value is /0, which
targets the whole Internet. The largest value is /32, which targets just the named host or
IP address because all address bits are fixed.
CIDR notation is short but not always flexible enough. For example, you might want to send
probes to 192.168.0.0/16 but skip any IPs ending with .0 or .255 because they may be used
as subnet network and broadcast addresses. Ncrack supports this through octet range
addressing. Rather than specify a normal IP address, you can specify a comma-separated
list of numbers or ranges for each octet. For example, 192.168.0-255.1-254 will skip all
addresses in the range that end in .0 or .255, and 192.168.3-5,7.1 will target the four
addresses 192.168.3.1, 192.168.4.1, 192.168.5.1, and 192.168.7.1. Either side of a range
may be omitted; the default values are 0 on the left and 255 on the right. Using - by
itself is the same as 0-255, but remember to use 0- in the first octet so the target
specification doesn´t look like a command-line option. Ranges need not be limited to the
final octets: the specifier will send probes to all IP addresses on the Internet ending in
13.37 This sort of broad sampling can be useful for Internet surveys and research.
Ncrack accepts multiple host specifications on the command line, and they don´t need to be
the same type. The command ncrack scanme.nmap.org 192.168.0.0/8 10.0.0,1,3-7.- -p22 does
what you would expect.
While targets are usually specified on the command lines, the following options are also
available to control target selection:
-iX inputfilename (Input from Nmap´s -oX XML output format) .
Reads target/service specifications from an Nmap XML output file. The Nmap XML file is
created by scanning any hosts and specifying the Nmap -oX option. Ncrack will
automatically parse the IP addresses and the corresponding ports and services that are
open and will use these targets for authentication auditing. This is a really useful
option, since it lets you essentially combine these two tools -Nmap and Ncrack- for
cracking only those services that are surely open. In addition, if version detection
has been enabled in Nmap (-sV option), Ncrack will use those findings to recognize and
crack those services that are supported but are listening on non-default ports. For
example, if a host is having a server listening on port 41414 and Nmap has identified
that it is a SSH service, Ncrack will use that information to crack it using the SSH
module. Of course, Ncrack is going to ignore open ports/services that are not
supported for authentication cracking by its modules.
-iN inputfilename (Input from Nmap´s -oN Normal output format) .
Reads target/service specifications from an Nmap Normal output file. The Nmap Normal
file is created by scanning any hosts and specifying the Nmap -oN option. This works
exactly like Ncrack´s -iX option, the only difference being the format of the input
file.
-iL inputfilename (Input from list) .
Reads target specifications from inputfilename. Passing a huge list of hosts is often
awkward on the command line, yet it is a common desire. For example, you might want to
crack a list of very specific servers that have been specified for penetration
testing. Simply generate the list of hosts to crack and pass that filename to Ncrack
as an argument to the -iL option. Entries can be in any of the formats accepted by
Ncrack on the command line (IP address, hostname, CIDR, octet ranges or Ncrack´s
special host-service syntax. Each entry must be separated by one or more spaces, tabs,
or newlines. You can specify a hyphen (-) as the filename if you want Ncrack to read
hosts from standard input rather than an actual file. Note, however, that if hosts are
specified without any service, you will have to also provide services/ports for the
targets using the -p option.
--exclude host1[, host2[, ...]] (Exclude hosts/networks) .
Specifies a comma-separated list of targets to be excluded from the scan even if they
are part of the overall network range you specify. The list you pass in uses normal
Ncrack syntax, so it can include hostnames, CIDR netblocks, octet ranges, etc. This
can be useful when the network you wish to scan includes untouchable mission-critical
servers, systems that are known to react adversely to heavy load, or subnets
administered by other people.
--excludefile exclude_file (Exclude list from file) .
This offers the same functionality as the --exclude option, except that the excluded
targets are provided in a newline, space, or tab delimited exclude_file rather than on
the command line.
SERVICE SPECIFICATION
No cracking session can be carried out without targeting a certain service to attack.
Service specification is one of the most flexible subsystems of Ncrack and collaborates
with target-specification in a way that allows different option combinations to be
applied. For Ncrack to start running, you will have to specify at least one target host
and one associated service to attack. Ncrack provides ways to specify a service by its
default port number, by its name (as extracted from the ncrack-services file) or both.
Normally, you need to define both name and port number only in the special case where you
know that a particular service is listening on a non-default port.
Ncrack offers two distinct ways with which services will be applied to your targets:
per-host service specification and global specification.
Per-host service specification
Services specified in this mode are written next to the host and apply to it only.
Keep in mind, however, that target-specification allows wildcards/netmasks, which
essentially means that applying a per-host service specification format to that
particular target will affect all of the expanded ones as a result. The general format
is:
[service-name]://target:[port-number]
where target is a hostname or IP address in any of the formats described in the
target-specification section, [service-name] is one of the common service names as
defined in the ncrack-services file (e.g ssh, http) and [port-number] is what it
obviously means. Ncrack can determine the default port numbers for each of the
services it supports, as well as being able to deduce the service name when a default
port number has been specified. Specifying both has meaning only when the user has a
priori knowledge of a service listening on a non-default port number. This can easily
be determined by using version detection like the one offered by Nmap´s -sV option.
Example 2. Per-host service specification example
$ ncrack scanme.nmap.org:22 ftp://10.0.0.10 ssh://192.168.1.*:5910
The above command will try to crack hosts: scanme.nmap.org on SSH service (default
port 22), 10.0.0.10 on FTP service (default port 21) and 192.168.1.0 - 192.168.1.255
(all of this C subnet) on SSH service on non-default port 5910 which has been
explicitly specified. In the last case, Ncrack wouldn´t be able to determine that the
subnet hosts are to be scanned against the SSH service on that particular port without
the user explicitly asking for it, because there isn´t any mapping of port-number 5910
to service SSH.
Global service specification
Services specified in this mode are applied to all hosts that haven´t been associated
with the per-host service specification format. This is done using the -p option.
While this facility may be similar to that of Nmap´s, you should try not to confuse
it, since the functionality is of a slightly different nature. Services can be
specified using comma separated directives of the general format:
-p [service1]:[port-number1],[service2]:[port-number2],...
As usual, you need not specify both service name and port number since Ncrack knows
the mappings of default-services to default-port numbers. Be careful though not to
include any space between each service-name and/or port number, because Ncrack will
think that the argument after the space is a host as per the rule "everything that
isn´t an option is a target specification".
Example 3. Global service specification example
$ ncrack scanme.nmap.org 10.0.0.120-122 192.168.2.0/24 -p 22,ftp:3210,telnet
The above command will try to crack all of the specified hosts scanme.nmap.org,
10.0.0.120, 10.0.0.121, 10.0.0.122 and the C class subnet of 192.168.2.0 against the
following services: SSH service (mapped from default port 22), FTP service on
non-default port 3210, and TELNET service on default port 23.
Of course, Ncrack allows you to combine both modes of service specification if you deem
that as necessary. Normally, you will only need to specify a couple of services but
cracking a lot of hosts against many different services might be a longterm project for
large networks that need to be consistently audited for weak passwords. If you are in
doubt, about which hosts and services are going to be cracked with the current command,
you can use the -sL option (see below for explanation).
SERVICE OPTIONS
Apart from general service specification, Ncrack allows you to provide a multitude of
options that apply to each or a subset of your targets. Options include timing and
performance optimizations (which are thoroughly analyzed in a separate section), SSL
enabling/disabling and other module-specific parameters like the relative URL path for the
HTTP module. Options can be defined in a variety of ways which include: per-host options,
per-module options and global options. Since a combination of these options may be used,
there is a strict hierarchy of precedence which will be discussed later.
Per-host Options
Options in this mode apply only to the host(s) they are referring to and are written
next to it according to the following format:
[service-name]://target:[port-number],opt1=optval1,opt2=optval,...
The format concerning the service specification which comes before the options, has
been explained in the previous section. optN is referring to any of the option names
that are available (a list will follow below), while optvalN determines the value of
that option and depends on the nature of it. For example, most timing-related options
expect to receive numbers as values, while the path option obviously needs a string
argument.
Per-module Options
Options in this mode apply to all hosts that are associated with the particular
service/module. This is accomplished using the -m which is defined with the format:
-m service-name:opt1=optval1,opt2=optval2,...
This option can be invoked multiple times, for as many different services as you might
need to define service-wide applicable options. Each iteration of this option must
refer to only one service. However, to avoid confusion, this option had better not be
called more than one time for the same service, although this is allowed and the last
iteration will take precedence over the previous ones for all redefined option values.
Global Options
Options in this mode apply to all hosts regardless of which service they are
associated with. This is accomplished using the -g as follows:
-g opt1=optval1,opt2=optval2,...
This acts as a convenience option, where you can apply options to all services
globally. Everything else regarding the available options and option values is the
same as the previous modes.
List of available Service Options
Below follows a list of all the currently available service options. You can apply them
with any of the three modes described above. The last six of the options are timing
related and will be analyzed in Section "Timing and Performance" of this manual.
ssl: enable SSL over this service
path: path-name used in modules like HTTP (´=´ needs escaping if used)
db: used in modules like MongoDB to specify the database
domain: used in modules like WinRM to specify the domain
cl (min connection limit): minimum number of concurrent parallel connections
CL (max connection limit): maximum number of concurrent parallel connections
at (authentication tries): authentication attempts per connection
cd (connection delay): delay time between each connection initiation
cr (connection retries): caps number of service connection attempts
to (time-out): maximum cracking time for service, regardless of success so far
ssl (Enable/Disable SSL over service)
By enabling SSL, Ncrack will try to open a TCP connection and then negotiate a SSL
session with the target. Everything will then be transparently encrypted and
decrypted. However, since Ncrack´s job is to provide speed rather than strong crypto,
the algorithms and ciphers for SSL are chosen on an efficiency basis. Possible values
for this option are ´yes´ but just specifying ssl would be enough. Thus, this is the
only option that doesn´t need to be written in the opt=optval format. By default, SSL
is disabled for all services except those that are stricly dependent on it like HTTPS.
path <name> (Path name for relative URLs)
Some services like HTTP or SVN usually require a specific path in the URL. This option
takes that pathname string as its value. The path is always relative to the hostname
or IP address, so if you want to target something like http://foobar.com/login.php the
path must take the value path=login.php . The initial ´/´ is added if you omit it.
However, it is usually better if you explicitly specify it at the end of pathnames
that are directories. For example, to crack the directory for
http://foobar.com/protected-dir/ , it would be better if you wrote it as
path=protected-dir/ . This is to avoid the (very) slight probability of a false
positive, because there are cases where Web servers might reply with a "301 Moved
Permanently" for a non-successful attempt. They normally send that reply, when a
successful attempt is made for a requested password-protected path which has omitted
the ending ´/´ but the requested source is actually a directory. Consequently, Ncrack
regards that reply as having succeeded in the authentication attempt.
Also be careful with the symbol ´=´, since it is used by Ncrack for argument parsing
and you will have to espace it if it is included in the URL.
By default, the path-name is initialized to ´/´, but will be ignored by services that
do not require it.
db <name> (Database name)
Some services like MongoDB require a specific database name to crack. This option
allows you to specify the database.
By default, the db name for MongoDB is initialized to ´admin´ but will be ignored by
services that do not require it.
domain <name> (Domain name)
Some services like WinRM require a specific domain to crack. This option allows you to
specify the domain.
By default, the domain name for WinRM is initialized to ´Workstation´ but will be
ignored by services that do not require it.
Service Option Hierarchy
As already noted, Ncrack allows a combination of the three different modes of service
option specification. In that case, there is a strict hierarchy that resolves the order in
which conflicting values for these options take precedence over each other. The order is
as follows, leftmost being the highest priority and rightmost the lowest one:
Per-host options > Per-module options > Global options > Timing-Template (for timing
options only)
The concept of the "Timing-Template" will be explained in the Section "Timing and
Performance", but for now, just have in mind that its values have the least prevalence
over everything else and essentially act as defaults for everything timing-related. Global
options specified with -g have the directly higher precedence, while -m per-module options
are immediately higher. In the top of the hierarcy reside the per-host options which are
essentially the most specific ones. Consequently, you can see that the pattern is: the
more specific the higher the precedence.
Example 4. Service Option Hierarchy example
$ ncrack scanme.nmap.org:22,cl=10,at=1 10.0.0.120 10.0.0.20 -p 21 -m ftp:CL=1 -g CL=3
The example demonstrates the hierarchy precedence. The services that are going to be
cracked are SSH for scanme.nmap.org and FTP for hosts 10.0.0.120, 10.0.0.20. No particular
timing-template has been specified and thus the default will be used (Normal - 3). The
per-host options for scanme.nmap.org define that the minimum connection limit (cl) is 10
and that Ncrack should attempt only 1 authentication try (at) per connection. These values
would override any other for service SSH of host scanme.nmap.org if there were conflicts
with other modes. Since a global option of -g CL=3 was defined and there is no other
higher-precedence for service SSH and scanme.nmap.org in particular, this value will also
be applied. As for the FTP targets, the per-module -m ftp:CL=1 defined for all FTP
services will override the equivalent global one. All these can get quite complex if
overused, but they are not expected to be leveraged by the average Ncrack user anyway.
Complicated network scanning scenarios might require them, though. To make certain the
results are the ones you expect them to be, don´t forget to use the -sL option that prints
out details about what Ncrack would crack if invoked normally. You can add the debugging
-d option if you want even more verbose output. For the above example, Ncrack would print
the following:
Example 5. Service Option Hierarchy Output example
$ ncrack scanme.nmap.org:22,cl=10,at=1 10.0.0.120 10.0.0.20 -p 21 -m ftp:CL=1 -g CL=3 -sL -d
Starting Ncrack 0.6 ( http://ncrack.org ) at 2017-10-12 01:13 CDT
----- [ Timing Template ] -----
cl=7, CL=80, at=0, cd=0, cr=30, to=0
----- [ ServicesTable ] -----
SERVICE cl CL at cd cr to ssl path db domain
ftp:21 N/A 1 N/A N/A N/A N/A no null null null
ssh:22 N/A N/A N/A N/A N/A N/A no null null null
telnet:23 N/A N/A N/A N/A N/A N/A no null null null
http:80 N/A N/A N/A N/A N/A N/A no null null null
pop3:110 N/A N/A N/A N/A N/A N/A no null null null
imap:143 N/A N/A N/A N/A N/A N/A no null null null
netbios-ssn:445 N/A N/A N/A N/A N/A N/A no null null null
smb:445 N/A N/A N/A N/A N/A N/A no null null null
smb:139 N/A N/A N/A N/A N/A N/A no null null null
https:443 N/A N/A N/A N/A N/A N/A yes null null null
owa:443 N/A N/A N/A N/A N/A N/A yes null null null
sip:5060 N/A N/A N/A N/A N/A N/A no null null null
pop3s:995 N/A N/A N/A N/A N/A N/A yes null null null
mssql:1433 N/A N/A N/A N/A N/A N/A no null null null
mysql:3306 N/A N/A N/A N/A N/A N/A no null null null
ms-wbt-server:3389 N/A N/A N/A N/A N/A N/A no null null null
rdp:3389 N/A N/A N/A N/A N/A N/A no null null null
psql:5432 N/A N/A N/A N/A N/A N/A no null null null
vnc:5801 N/A N/A N/A N/A N/A N/A no null null null
vnc:5900 N/A N/A N/A N/A N/A N/A no null null null
vnc:5901 N/A N/A N/A N/A N/A N/A no null null null
vnc:6001 N/A N/A N/A N/A N/A N/A no null null null
redis:6379 N/A N/A N/A N/A N/A N/A no null null null
winrm:5985 N/A N/A N/A N/A N/A N/A no null null Workstation
winrm:5986 N/A N/A N/A N/A N/A N/A no null null Workstation
cassandra:9160 N/A N/A N/A N/A N/A N/A no null null null
cassandra:9042 N/A N/A N/A N/A N/A N/A no null null null
mongodb:27017 N/A N/A N/A N/A N/A N/A no null admin null
----- [ Targets ] -----
Host: 45.33.32.156 ( scanme.nmap.org )
ssh:22 cl=10, CL=10, at=1, cd=0, cr=30, to=0ms, ssl=no, path=/, db=admin, domain=Workstation
Host: 10.0.0.120
ftp:21 cl=3, CL=1, at=0, cd=0, cr=30, to=0ms, ssl=no, path=/, db=admin, domain=Workstation
Host: 10.0.0.20
ftp:21 cl=3, CL=1, at=0, cd=0, cr=30, to=0ms, ssl=no, path=/, db=admin, domain=Workstation
Ncrack done: 3 services would be scanned.
Probes sent: 0 | timed-out: 0 | prematurely-closed: 0
Ncrack finished.
The ServicesTable just lists the per-module options for all available services. As you can
see, the only defined option is in the FTP service for the CL . The Targets table is the
most important part of this output and lists all targets and associated options according
to the command-line invocation. No network operation takes place in this mode, apart from
forward DNS resolution for hostnames (like scanme.nmap.org in this example).
TIMING AND PERFORMANCE
The timing engine is perhaps the most important part of any serious network authentication
cracking tool. Ncrack´s timing engine offers a great many options for optimization and can
be bended to serve virtually any user need. As Ncrack is progressing, this subsystem is
going to evolve into a dynamic autonomous engine that will be able to automatically adjust
its behaviour according to the network feedback it gets, in order to achieve maximum
performance and precision without any user intervention.
Some options accept a time parameter. This is specified in seconds by default, though you
can append ‘ms’, ‘m’, or ‘h’ to the value to specify milliseconds, minutes, or hours (‘s’
for seconds is redundant). So the cd (connection delay) arguments 900000ms, 900s, and 15m
all do the same thing.
cl num-minconnections; CL num-maxconnections (Adjust number of concurrent parallel
connections)
Connection Limit
These options control the total number of connections that may be outstanding for any
service at the same time. Normally, Ncrack tries to dynamically adjust the number of
connections for each individual target by counting how many drops or connection
failures happen. If a strange network condition occurs, that signifies that something
may be going wrong, like the host dropping any new connection attempts, then Ncrack
will immediately lower the total number of connections hitting the service. However,
the caps number of the minimum or maximum connections that will take place can be
overridden using these two options. By properly adjusting them, you can essentially
optimize performance, if you can handle the tricky part of knowing or discovering your
target´s own limits. The convention here is that cl with lowercase letters is
referring to the minimum connection limit, while CL with uppercase letters is
referring to the maximum number of connections.
The most common usage is to set cl (minimum connection limit) for targets that you are
almost certain are going to withstand these many connections at any given time. This
is a risky option to play with, as setting it too high might actually do more harm
than good by effectively DoS-attacking the target and triggering firewall rules that
will ban your IP address.
On the other hand, for more stealthy missions, setting the CL (maximum connection
limit) to a low value might be what you want. However, setting it too low will surely
have a great impact in overall cracking speed. For maximum stealth, this can be
combined with the cd (connection delay) described below.
at num-attempts (Adjust authentication attempts per connection)
Authentication Tries
Using this option, you can order Ncrack to limit the authentication attempts it
carries out per connection. Ncrack initially sends a reconnaisance probe that lets it
calculate the maximum number of such authentication tries and from thereon it always
tries to use that number. Most servicse pose an upper limit on the number of
authentication per connection and in most cases finding that maximum leads to better
performance.
Setting this option to lower values can give you some stealth bonus, since services
such as SSH tend to log failed attempts after more than a certain number of
authentication tries per connection. They use that as a metric rather than counting
the total number of authentication attempts or connections per IP address (which is
usually done by a firewall). Consequently, a number of 1 or 2 authentication tries
might circumvent logging in some cases.
Note that setting that option to a high value will not have any effect if Ncrack
realizes that the server doesn´t allow that many attempts per connection. In this
case, it will just use that maximum number and ignore your setting.
cd time (Adjust delay time between each new connection)
Connection Delay
This option essentially defines the imposed time delay between each new connection.
Ncrack will wait the amount of time you specify in this option value, before starting
a new connection against the given service. The higher you set it, the slower Ncrack
will perform, but the stealthier your attack will become.
Ncrack by default tries to initiate new connections as fast as possible given that new
probes are actually allowed to be sent and are not restricted by parameters such as
Connection Limit which can dynamically increase or decrease. Although this approach
achieves blazing speed as long as the host remains responsive, it can lead to a number
of disasters such as a firewall being triggered, the targets´ or your bandwidth to be
diminished and even the tested service to suffer a Denial of Service attack. By
carefully adjusting this option, you can potentially avoid these annoying situations.
cr max-conattempts (Adjust the max number of connection retries)
Connection Retries
This option allows the user to specify the maximum amount of consecutive failed
attempts against that particular service. If at any time, during the cracking session,
Ncrack fails to connect against that particular service, then it will stop cracking it
entirely.
to time (Adjust the maximum overall cracking time)
Timeout
Define how much time Ncrack is going to spend cracking the service, before giving up
regardless of whether it has found any credentials so far. However, any authentication
token discovered until that time, will be stored and printed normally. Ncrack marks a
service as finished when the username/password lists iteration ends or when it can no
longer crack it for some serious reason. If Ncrack finishes cracking a service before
the time specified in this option, then it will not be taken into account at all.
Sometimes, you have a limited time window to scan/crack your hosts. This might occur
for various reasons. A common one would be that normal user activity mustn´t be
interrupted and since Ncrack can become very aggressive, it might be allowed to scan
the hosts only at during certain time period like the night hours. Scanning during
certain such hours is also likely to make an attack less detectable.
Don´t forget that Ncrack allows you to specify the time unit of measure by appending
‘ms’, ‘m’, or ‘h’ for milliseconds, minutes or hours (seconds is the default time
unit). Using them in this particular option, is really convenient as you can specify
something like to=8h to give Ncrack a total of 8 hours to crack that service. Setting
up cronjobs for scheduled scans in combination with this option, might also be a good
idea.
-T paranoid|sneaky|polite|normal|aggressive|insane (Set a timing template) .
While the fine-grained timing controls discussed in the previous section are powerful
and effective, some people find them confusing. Moreover, choosing the appropriate
values can sometimes take more time than the scan you are trying to optimize. So
Ncrack offers a simpler approach, with six timing templates. You can specify them with
the -T option and their number (0–5) or their name. The template names are
paranoid (0), sneaky (1), polite (2), normal (3), aggressive (4), and insane (5). The
first two are for IDS evasion. Polite mode slows down the scan to use less bandwidth
and target machine resources. Normal mode is the default and so -T3 does nothing.
Aggressive mode speeds scans up by making the assumption that you are on a reasonably
fast and reliable network. Finally insane mode assumes that you are on an
extraordinarily fast network or are willing to sacrifice some accuracy for speed.
These templates allow the user to specify how aggressive they wish to be, while
leaving Ncrack to pick the exact timing values. If you know that the network service
is going to withstand a huge number of connections you might try using the aggressive
template of -T4 . Even then, this is mostly advised for services residing in the local
network. Going over to insane mode -T5 is not recommended, unless you absolutely know
what you are doing.
While -T0. and -T1. may be useful for avoiding IDS alerts, they will take an
extraordinarily long time to crack even a few services. For such a long scan, you may
prefer to set the exact timing values you need rather than rely on the canned -T0 and
-T1 values.
--connection-limit numprobes (Adjust the threshold of total concurrent connections)
NOT IMPLEMENTED YET.
AUTHENTICATION
This section describes ways of specifying your own username and password lists as well as
the available modes of iterating over them. Ncrack ships in with a variety of username and
password lists which reside under the directory ´lists´ of the source tarball and later
installed under Ncrack´s data directory which usually is /usr/local/share/ncrack or
/usr/share/ncrack . You can omit specifying any lists and Ncrack is going to use the
default ones which contain some of the most common usernames and passwords. The password
list is frequency-sorted with the top most common passwords at the beginning of the list
so they will be tried out first. The lists have been derived from a combination of sorting
publicly leaked password files and other techniques.
-U filename (Specify username list)
Specify your own username list by giving the path to the filename as argument to this
option.
Usernames for specific environments can be gathered in numerous ways including
harvesting for email-addresses in the company´s website, looking up information in
whois databases, using the SMTP VRFY technique at vulnerable mail servers or through
social engineering.
-P filename (Specify password list)
Specify your own password list by giving the path to the filename as argument to this
option.
Common passwords are usually derived from leaked lists as a result of successful
intrusions in public sites such as forums or other social networking places. A great
deal of them have already been publicly disclosed and some of these have been used to
assemble Ncrack´s own lists.
--user username_list (Specify command-line comma-separated username list)
Specify your own usernames directly in the command-line as a comma-separated list.
--pass password_list (Specify command-line comma-separated password list)
Specify your own passwords directly in the command-line as a comma-separated list.
--passwords-first (Reverse the way passwords are iterated)
Ncrack by default iterates the username list for each password. With this option, you
can reverse that. For example, given the username list of -> "root, guest, admin" and
the password list of "test, 12345, q1w2e3r4" Ncrack will normally go over them like
this -> root:test, guest:test, admin:test, root:12345 etc. By enabling this option it
will go over them like this -> root:test, root:12345, root:q1w2e3r4, guest:test etc.
Most network authentication cracking tools prefer by default to iterate the password
list for each username. This is, however, ineffective compared to the opposite
iteration in most cases. This holds true for the simple reason that password lists are
usually sorted on a frequency basis, meaning that the more common a password is, the
closer to the beginning of the password list it is. Thus, iterating over all usernames
for the most common passwords first has usually more chances to get a positive result.
With the --passwords-first iteration, very common passwords might not even be tried
out for certain usernames if the user chooses to abort the session early. However,
this option might prove valuable for cases where the attacker knows and has already
verified that the username list contains real usernames, instead of blindly
bruteforcing through them.
--pairwise (Choose usernames and passwords in pairs)
Enabling this option will make Ncrack iterate the username and password list by
choosing them in pairs. For example, given the username list of "root, guest, admin"
and the password list of "test, 12345, q1w2e3r4" Ncrack will go over them like this:
"root:test", "guest:12345", "admin:q1w2e3r4". This is particularly useful when inside
knowledge of the infrastructure tested is available and special username and password
lists have been made.
OUTPUT
Any security tool is only as useful as the output it generates. Complex tests and
algorithms are of little value if they aren´t presented in an organized and comprehensible
fashion. Of course, no single format can please everyone. So Ncrack offers several
formats, including the interactive mode for humans to read directly and XML for easy
parsing by software.
In addition to offering different output formats, Ncrack provides options for controlling
the verbosity of output as well as debugging messages. Output types may be sent to
standard output or to named files, which Ncrack can append to or clobber.
Ncrack makes output available in three different formats. The default is called
interactive output, and it is sent to standard output (stdout). There is also normal
output, which is similar to interactive except that it displays less runtime information
and warnings since it is expected to be analyzed after the scan completes rather than
interactively.
XML output is one of the most important output types, as it can be converted to HTML,
easily parsed by programs such as Ncrack graphical user interfaces, or imported into
databases. Currently, XML output hasn´t been implemented.
While interactive output is the default and has no associated command-line options, the
other two format options use the same syntax. They take one argument, which is the
filename that results should be stored in. Multiple formats may be specified, but each
format may only be specified once. For example, you may wish to save normal output for
your own review while saving XML of the same scan for programmatic analysis. You might do
this with the options -oX myscan.xml -oN myscan.ncrack. While this chapter uses the simple
names like myscan.xml for brevity, more descriptive names are generally recommended. The
names chosen are a matter of personal preference. A scheme could be using long filenames
that incorporate the scan date and a word or two describing the scan, placed in a
directory named after the company that is being scanned.
While these options save results to files, Ncrack still prints interactive output to
stdout as usual. For example, the command nmap -oX myscan.xml [target] prints XML to
myscan.xml and fills standard output with the same interactive results it would have
printed if -oX wasn´t specified at all. You can change this by passing a hyphen character
as the argument to one of the format types. This causes Ncrack to deactivate interactive
output, and instead print results in the format you specified to the standard output
stream. So the command nmap -oX - target will send only XML output to stdout. Serious
errors may still be printed to the normal error stream, stderr.
Unlike some Ncrack arguments, the space between the logfile option flag (such as -oX) and
the filename or hyphen is mandatory.
All of these arguments support strftime-like conversions in the filename. %H, %M, %S, %m,
%d, %y, and %Y are all exactly the same as in strftime. %T is the same as %H%M%S, %R is
the same as %H%M, and %D is the same as %m%d%y. A % followed by any other character just
yields that character (%% gives you a percent symbol). So -oX ´scan-%T-%D.xml´ will use an
XML file in the form of scan-144840-121307.xml.
Ncrack also offers options to control scan verbosity and to append to output files rather
than clobbering them. All of these options are described below.
Ncrack Output Formats
-oN filespec (normal output) .
Requests that normal output be directed to the given filename. As discussed above,
this differs slightly from interactive output.
-oX filespec (XML output) .
Requests that XML output be directed to the given filename.
-oA basename (Output to all formats) .
As a convenience, you may specify -oA basename to store scan results in normal and XML
formats at once. They are stored in basename.ncrack, and basename.xml respectively. As
with most programs, you can prefix the filenames with a directory path, such as
~/ncracklogs/foocorp/ on Unix or c:\hacking\sco on Windows.
Verbosity and debugging options
-v (Increase verbosity level) .
Increases the verbosity level, causing Ncrack to print more information about the scan
in progress. Credentials are shown as they are found and more statistical information
is printed in the end. Use it twice or more for even greater verbosity.
-d [level] (Increase or set debugging level) .
When even verbose mode doesn´t provide sufficient data for you, debugging is available
to flood you with much more! As with the verbosity option (-v), debugging is enabled
with a command-line flag (-d) and the debug level can be increased by specifying it
multiple times. Alternatively, you can set a debug level by giving an argument to -d.
For example, -d10 sets level ten. That is the highest effective level and will produce
thousands of lines, unless your cracking session is going really slow.
Debugging output is useful when a bug is suspected in Ncrack, or if you are simply
confused as to what Ncrack is doing and why. As this feature is mostly intended for
developers, debug lines aren´t always self-explanatory. If you don´t understand a
line, your only recourses are to ignore it, look it up in the source code, or request
help from the development list (nmap-dev). Some lines are self explanatory, but the
messages become more obscure as the debug level is increased.
--nsock-trace level (Set nsock trace level) .
This option is meant mostly for developers as enabling it will activate the Nsock´s
library debugging output. Nsock is the underlying library for parallel socket
handling. You will have to specify a certain level for this option. Valid range is 0
up to 10. Usually, a level of 1 or 2 is enough to get a good overview of network
operations happening behind the scenes. Nsock prints that information to stdout by
default.
--log-errors (Log errors/warnings to normal mode output file) .
Warnings and errors printed by Ncrack usually go only to the screen (interactive
output), leaving any normal-format output files (usually specified with -oN)
uncluttered. When you do want to see those messages in the normal output file you
specified, add this option. It is useful when you aren´t watching the interactive
output or when you want to record errors while debugging a problem. The error and
warning messages will still appear in interactive mode too. This won´t work for most
errors related to bad command-line arguments because Ncrack may not have initialized
its output files yet.
An alternative to --log-errors is redirecting interactive output (including the
standard error stream) to a file. Most Unix shells make this approach easy, though it
can be difficult on Windows.
Miscellaneous output options
--append-output (Append to rather than clobber output files) .
When you specify a filename to an output format flag such as -oX or -oN, that file is
overwritten by default. If you prefer to keep the existing content of the file and
append the new results, specify the --append-output option. All output filenames
specified in that Ncrack execution will then be appended to rather than clobbered.
This doesn´t work well for XML (-oX) scan data as the resultant file generally won´t
parse properly until you fix it up by hand.
MISCELLANEOUS OPTIONS
This section describes some important (and not-so-important) options that don´t really fit
anywhere else.
--resume file (Continue previously saved session) .
Whenever the user cancels a running session (usually by pressing Ctrl+C), Ncrack saves
the current state into a file which it can later use to continue from where it had
stopped. This file is saved in subdirectory .ncrack/ of the user´s home path with a
filename format of "restore.YY-MM-DD_hh-mm". An example would be:
"/home/ithilgore/.ncrack/restore.2010-05-18_04-42". You can then continue your
session, by specifying this file as argument to the --resume option.
-f (Quit cracking service after one found credential) .
This option will force Ncrack to quit cracking a service as soon as it finds a valid
username/password combination for it. Assuming many parallel services are being
cracked at the same time, this option is applied on each of them separately. This
means that Ncrack will stop cracking each individual service after finding a pair of
credentials for it, but will not quit entirely. Supplying the option two times, like
-f -f will, however, make Ncrack exit immediately as soon as it finds a valid
credential for any service.
Frequently, attackers will try cracking several services in parallel to maximize the
chances of finding a pair of valid credentials. Given that a network is no stronger
than its weakest link, this option and especially the -f -f counterpart will often be
used to lessen chances of detection and prevent network resources from being wasted
aimlessly.
-6 (Enable IPv6 scanning) .
Warning: This option was just added and it is currently experimental, so please notify
us for any problems and bugs related to it.
The command syntax is the same as usual except that you also add the -6 option. Of
course, you must use IPv6 syntax if you specify an address rather than a hostname. An
address might look like 3ffe:7501:4819:2000:210:f3ff:fe03:14d0, so hostnames are
recommended. The output looks the same as usual, with the IPv6 address on the
“Discovered credentials” line being the only IPv6 give away.
While IPv6 hasn´t exactly taken the world by storm, it gets significant use in some
(usually Asian) countries and most modern operating systems support it. To use Ncrack
with IPv6, both the source and target of your scan must be configured for IPv6. If
your ISP (like most of them) does not allocate IPv6 addresses to you, free tunnel
brokers are widely available and will probably work fine with Ncrack. A popular IPv6
tunnel broker service is at http://www.tunnelbroker.net. 6to4 tunnels are another
popular, free approach.
-sL (List Scan) .
The list scan simply lists each host and service that would be cracked if this option
wasn´t specified. No packets are sent to the target hosts and the only network
operation that might happen is DNS-resolution of any hostnames of targets. This option
is really helpful in making sure that you have specified everything as you wanted.
Service-specific options will also be printed so this acts as a good sanity check of
potentially complex command-line arguments such as the advanced modes of Service
Option Specification and the equivalent Hierarchy for sessions that require delicate
timing handling. If list scan is called along with the -d debug option, then
additional output, like the ServicesTable and the current Timing-Template´s
parameters, is also going to be printed.
--datadir directoryname (Specify custom Ncrack data file location) .
Ncrack needs a file called ncrack-services to load a lookup-table of supported
services/ports. This file shouldn´t be changed, unless you know what you are doing
(e.g extending Ncrack for additional modules). In addition, Ncrack is shipped with
various username and password lists, some of which are used by default in case the
user doesn´t specify ones of his own. All these files are normally copied during the
installation procedure to a directory such as /usr/share/ncrack or
/usr/local/share/ncrack . Using the --datadir option, will force Ncrack to start
searching for these files in specified directory. If the files aren´t found, then it
will continue searching in the directory specified by the NCRACKDIR environmental
variable NCRACKDIR (if it is defined). Next comes ~/.ncrack directory for real and
effective UIDs (POSIX systems only) or location of the Ncrack executable (Win32 only),
and then a compiled-in location such as /usr/local/share/ncrack or /usr/share/ncrack.
As a last resort, Ncrack will look in the current directory.
--proxy type://proxy:port (Make connections via socks4, 4a, http) .
This will make Ncrack perform the authentication cracking session through the proxy
host specified.
-V; --version (Print version number) .
Prints the Ncrack version number and exits.
-h; --help (Print help summary page) .
Prints a short help screen with the most common command flags. Running Ncrack without
any arguments does the same thing.
RUNTIME INTERACTION
During the execution of Ncrack, all key presses are captured. This allows you to interact
with the program without aborting and restarting it. Certain special keys will change
options, while any other keys will print out a status message telling you about the scan.
The convention is that lowercase letters increase the amount of printing, and uppercase
letters decrease the printing. You may also press ‘?’ for help.
v / V
Increase / decrease the verbosity level
d / D
Increase / decrease the debugging Level
p / P
Display found credentials
?
Print a runtime interaction help screen
Anything else
Print out a status message like this:
Stats: 0:00:20 elapsed; 0 services completed (1 total)
Rate: 6.26; Found: 1; About 13.27% done; ETC: 21:06 (0:02:17 remaining)
MODULES
Ncrack´s architecture is modular with each module corresponding to one particular service
or protocol. Currently, Ncrack supports the protocols SSH, RDP, FTP, Telnet, HTTP(S),
POP3(S), IMAP, SMB, VNC, SIP Redis, PostgreSQL, MySQL, MSSQL, MongoDB, Cassandra, WinRM,
OWA. If you want to write and contribute your own Ncrack modules, be sure to read the
Ncrack Developer´s Guide at http://nmap.org/ncrack/devguide.html Below we describe some
key points for each of them.
FTP Module
FTP authentication is quite fast, since there is very little protocol negotiation
overhead. Most FTP daemons allow 3 to 6 authentication attempts but usually impose a
certain delay before replying with the results of a failed attempt. Filezilla is one
of the most characteristic examples of this case, where the time delay is so great,
that it is usually faster to open more connections against it, with each of them doing
only 1 authentication per connection.
Telnet Module
Telnet daemons have been largely substituted by their safer ´counterpart´ of SSH.
However, there are many boxes, mainly routers or printers, that still rely on Telnet
for remote access. Usually these are also easier to crack, since default passwords for
them are publicly known. The drawback is that telnet is a rather slow protocol, so you
shouldn´t be expecting really high rates against it.
SSH Module
SSH is one of the most prevalent protocols in today´s networks. For this reason, a
special library, named opensshlib and based on code from OpenSSH, was specifically
built and tailored for Ncrack´s needs. Opensshlib ships in with Ncrack, so SSH support
comes out of the box. OpenSSL will have to be installed in Unix systems though.
Windows OpenSSL dlls are included in Ncrack, so Windows users shouldn´t be worrying
about it at all.
SSH bruteforcing holds many pitfalls and challenges, and you are well advised to read
a paper that was written to explain them. The latest version of the "Hacking the
OpenSSH library for Ncrack" document can be found under docs/openssh_library.txt or at
http://sock-raw.org/papers/openssh_library
HTTP(S) Module
The HTTP Module currently supports basic and digest authentication. Ncrack tries to
use the "Keepalive" HTTP option, whenever possible, which leads to really high speeds,
since that allows dozens of attempts to be carried out per connection. The HTTP module
can also be called over SSL.
SMB Module
The SMB module currently works over raw TCP. NetBIOS isn´t supported yet. This
protocol allows for high parallelization, so users could potentially increase the
number of concurrent probes against it. SMB is frequently used for file-sharing among
other things and is one of the most ubiquitous protocols, being present in both Unix
and Windows environments.
RDP Module
RDP (Remote Desktop Protocol) is a proprietary protocol developed by Microsoft for the
purpose of providing remote terminal services by transferring graphics display
information from the remote computer to the user and transporting input commands from
the user to the remote computer. Fortunately, Microsoft recently decided to open the
protocol´s internal workings to the public and has provided official documentation,
which can be found at
http://msdn.microsoft.com/en-us/library/cc240445%28v=PROT.10%29.aspx
RDP is one of the most complex protocols, requiring the exchange of many packets, even
for just the authentication phase. For this reason, cracking it takes a lot of time
and this is probably the slowest module. The connection phase is briefly described at
http://msdn.microsoft.com/en-us/library/cc240452%28v=PROT.10%29.aspx where you can
also see a diagram of the various packets involved. Care must be taken against RDP
servers in Windows XP versions, since they can´t handle multiple connections at the
same time. It is advised to use a very slow timing template or even better limit the
maximum parallel connections using timing options such as CL (Connection Limit) or cd
(connection delay) against Windows XP (and relevant) RDP servers. Windows Vista and
above don´t suffer from the same limitation.
VNC Module
The VNC protocol has known widespread usage among Unix administrators and users for
remote graphical access. VNC is perhaps one of the most vulnerable protocols in terms
of brute-forcing, since it often requires a password without a corresponding username
for authentication. In addition, some versions of VNC impose an 8-character limit in
password length. You should consider adding the --passwords-first option when cracking
VNC systems to exploit the fact that the username often has no actual importance in
authentication.
POP3(S) Module
POP3 support is still experimental and hasn´t been thoroughly tested. You can expect
it to work against common mail servers, nevertheless.
IMAP Module
The Internet Message Access Protocol (IMAP) is used by email clients to retrieve email
messages from a mail server. The module sends the LOGIN command to authenticate. The
LOGIN command is the simplest, fastest and most supported authentication mechanism for
IMAP.
SIP Module
The Session Initiation Protocol is a text-based protocol, very similar to HTTP in its
structure. The most common application of SIP is in Internet telephony for voice and
video calls. Nearly all enterprises have infrastructure that supports conference calls
and part of them are based on SIP, making the authentication part a significant threat
vector.
Redis Module
Redis is one of the most widely used caching servers and the most popular NoSQL
database. Despite its reputation, the authentication mechanism is very simple, only
allowing for a password to protect remote access to the service. Due to the high
performance of Redis and the fact that only 2 packets are needed for the
authentication phase, Ncrack can try a lot of passwords in parallel (‐
http://redis.io/commands/AUTH). Specifying a username list or single username will
have no effect in this module, since Redis only deals with passwords.
PostgreSQL Module
PostgreSQL is often used as a backend database. The PostgreSQL module supports md5
authentication, which is the most frequent password authentication method.
MySQL Module
The MySQL module supports native authentication.
MySQL Module
The MSSQL module supports mixed authentication.
MongoDB Module
The MongoDB module supports MongoDB-CR and SCRAM-SHA-1 authentication. The pairwise
and passwords-first option will be ignored for the MongoDB module, due to them being
inefficient against MongoDB. The optimal way of cracking MongoDB is to take advantage
of a user-enumeration vulnerability inherent in its authentication mechanism, which
Ncrack exploits.
Cassandra Module
Apache Cassandra is a popular NoSQL database often left unsecured with weak
credentials or no authentication.
OWA Module
Outlook Web App allows users to access a Microsoft Exchange Server mailbox from a web
browser and experience Microsoft Outlook without a mail client. The module supports
Basic Authentication.
WinRM Module
Windows Remote Management (WinRM) is the Microsoft implementation of WS-Management
Protocol, a standard Simple Object Access Protocol (SOAP)-based, firewall-friendly
protocol that allows hardware and operating systems, from different vendors, to
interoperate. It is often used to administer Windows machines. The module supports
Basic and Negotiate authentication.
DICOM Module
Digital Imaging and Communications in Medicine (DICOM) is a protocol used heavily in
healthcare environments. Most commonly, it is used as both a file format and network
protocol by Picture Archiving and Communication Systems (PACS). The client of a DICOM
service is called a service class user (SCU) and the server a service class provider
(SCP). DICOM is very unique in how it authenticates clients to servers; there are
potentially one to three steps involved: Association, Find Service and Retrieve
Images.
Association: This is the initial step that almost all PACS servers require. By sending
an A-ASSOCIATE request with the correct called Application Entity Title (AET) the
client associates with the server and then can go on to perform query / retrieve
requests in the next steps. This is the mode that Ncrack currently supports by
iterating through the username field. Thus to brute-force the server´s AET, you can
specify a list of AETs using the -U option and then specifying a null password.
Example: ncrack dicom://127.0.0.1 -U aet.txt --pass DOESNOTMATTER
Find Service: This step involves being able to query the PACS server for patient
studies that are associated with DICOM images. This takes place after the client has
performed the Association phase. A C-FIND request must be sent with the correct
calling AET. Knowing the correct allowed client AET (or calling AET) is required by
securely configured PACS servers. Many PACS servers by default do not require this.
Retrieve Images: This step allows a client to retrieve DICOM images. The most hardened
PACS servers will require the client to have a specific allowed IP configured in order
to send a C-MOVE / C-STORE request after the above two steps have been performed.
MQTT Module
The Message Queueing Telemetry Transport (MQTT) protocol is a publish / subscribe
machine to machine protocol that allows IoT clients to publish to a broker. Each
client device subscribes to a particular topic of interest and receives messages from
publishers. Usually MQTT authentication is optional and when enabled can be
brute-forced very easily as it only requires a single MQTT CONNECT packet to be sent
for each attempted credential pair.
Wordpress Module
Wodpress is one of the most popular content management systems. This module attacks
the web administration endpoint. By default it will try "wp-login.php" but you can
change it by specifying the path. For example: ncrack
wp://127.0.0.1,path=/non-default/wp-login.php
CVS Module
The Concurrent Versioning System (CVS) is a revision control system in software
development. Although not as popular nowadays, there are many old, oudated CVS servers
out there that might have default or weak credentials.
BUGS
Like its authors, Ncrack isn´t perfect. But you can help make it better by sending bug
reports or even writing patches. If Ncrack doesn´t behave the way you expect, first
upgrade to the latest version available from http://nmap.org/ncrack. If the problem
persists, do some research to determine whether it has already been discovered and
addressed. Try searching for the error message on our search page at
http://insecure.org/search.html or at Google. Also try browsing the nmap-dev archives at
http://seclists.org/ . Read this full manual page as well. If you are developing your own
Ncrack module, make sure you have first read the Ncrack Developer´s Guide at
http://nmap.org/ncrack/devguide.html . If nothing comes of this, mail a bug report to
nmap-dev@insecure.org . Please include everything you have learned about the problem, as
well as what version of Ncrack you are running and what operating system version it is
running on. Problem reports and Ncrack usage questions sent to nmap-dev@insecure.org are
far more likely to be answered than those sent to Fyodor directly. If you subscribe to the
nmap-dev list before posting, your message will bypass moderation and get through more
quickly. Subscribe at http://cgi.insecure.org/mailman/listinfo/nmap-dev .
Code patches to fix bugs are even better than bug reports. Basic instructions for creating
patch files with your changes are available at http://nmap.org/data/HACKING . Patches may
be sent to nmap-dev (recommended) or to Fyodor directly.
AUTHORS
ithilgore (Fotios (Fotis) Chantzis) ithilgore@sock-raw.org (http://sock-raw.org)
Fyodor fyodor@insecure.org (http://insecure.org)
NCRACK COPYRIGHT AND LICENSING
While it isn´t distributed with Nmap, Ncrack is part of the Nmap project and falls under
the same license and (non) warranty provisions, as described at
http://nmap.org/book/man-legal.html.