Provided by: openvas-scanner_5.1.3-2_amd64 
NAME
openvassd - The Scanner of the Open Vulnerability Assessment System (OpenVAS)
SYNOPSIS
openvassd [-v] [-h] [-c config-file] [-D] [-R] [-P] [-q] [-f]
DESCRIPTION
OpenVAS is a security auditing framework made up of several modules. The Scanner,
openvassd is in charge of executing many security tests against many target hosts in a
highly optimized way.
openvassd inspects the remote hosts and attempts to list all the vulnerabilities and
common misconfigurations that affects them. Note that openvassd will run in daemon mode by
default (unless you specify -f as an option).
OPTIONS
-c <config-file>, --config-file=<config-file>
Use the alternate configuration file instead of /etc/openvas/openvassd.conf
-f, --foreground
Make the scanner stay in foreground (non-daemon mode)
-v, --version
Writes the version number and exits
-h, --help
Show a summary of the commands
THE CONFIGURATION FILE
The default openvassd configuration file, /etc/openvas/openvassd.conf contains these
options:
plugins_folder
Contains the location of the plugins folder. This is usually
/var/lib/openvas/plugins, but you may change this.
logfile
path to the logfile. You can enter syslog if you want the openvassd messages to be
logged via syslogd You may also enter stderr if you want the openvassd logs to be
written on stderr. Because openvassd is a sensitive program, you should keep your
logs.
max_hosts
is maximum number of hosts to test at the same time which should be given to the
client (which can override it). This value must be computed given your bandwidth,
the number of hosts you want to test, your amount of memory and the horsepower of
your processor(s).
max_checks
is the number of plugins that will run against each host being tested. Note that
the total number of process will be max_checks x max_hosts so you need to find a
balance between these two options. Note that launching too many plugins at the same
time may disable the remote host, either temporarily (ie: inetd closes its ports)
or definitely (the remote host crash because it is asked to do too many things at
the same time), so be careful.
be_nice
If this option is set to 'yes', then each child forked by openvassd will nice(2)
itself to a very low priority. This may speed up your scan as the main openvassd
process will be able to continue to spew processes, and this guarantees that
openvassd does not deprives other important processes from their resources.
log_whole_attack
If this option is set to 'yes', openvassd will store the name, pid, date and target
of each plugin launched. This is helpful for monitoring and debugging purpose,
however this option might make openvassd fill your disk rather quickly.
log_plugins_name_at_load
If this option is set to 'yes', openvassd will log the name of each plugin being
loaded at startup, or each time it receives the HUP signal.
dumpfile
Some plugins might issue messages, most of the time to inform you that something
went wrong. If you want to read these messages, set this value to a given file
name. If you want to save space, set this option value to /dev/null
cgi_path
By default, openvassd looks for default CGIs in /cgi-bin and /scripts. You may
change these to something else to reflect the policy of your site. The syntax of
this option is the same as the shell $PATH variable: path1:path2:...
port_range
This is the default range of ports that the scanner plugins will probe. The syntax
of this option is flexible, it can be a single range ("1-1500"), several ports
("21,23,80"), several ranges of ports ("1-1500,32000-33000"). Note that you can
specify UDP and TCP ports by prefixing each range by T or U. For instance, the
following range will make openvassd scan UDP ports 1 to 1024 and TCP ports 1 to
65535 : "T:1-65535,U:1-1024".
optimize_test
By default, openvassd does not trust the remote host banners. It means that it will
check a webserver claiming to be IIS for Apache flaws, and so on. This behavior
might generate false positive and will slow the scan down somehow. If you are sure
the banners of the remote host have not been tampered with, you can safely enable
this option, which will force the plugins to perform their job only against the
services they have been designed to check.
checks_read_timeout
Number of seconds that the security checks will wait for when doing a recv(). You
should increase this value if you are running openvassd across a slow network slink
(testing a host via a dialup connection for instance)
timeout_retry
Number of retries when a socket connection attempt timesout.
time_between_request
Some devices do not appreciate quick connection establishment and termination
neither quick request. This option allows you to set a wait time between two
actions like to open a tcp socket, to send a request trought the open tcp socket,
and to close the tcp socket. This value should be given in miliseconds. If the set
value is 0 (default value), this option is disabled and there is no wait time
between requests.
non_simult_ports
Some services (in particular SMB) do not appreciate multiple connections at the
same time coming from the same host. This option allows you to prevent openvassd to
make two connections on the same given ports at the same time. The syntax of this
option is "port1[, port2....]". Note that you can use the KB notation of openvassd
to designate a service formally. Ex: "139, Services/www", will prevent openvassd
from making two connections at the same time on port 139 and on every port which
hosts a web server.
plugins_timeout
This is the maximum lifetime, in seconds of a plugin. It may happen that some
plugins are slow because of the way they are written or the way the remote server
behaves. This option allows you to make sure your scan is never caught in an
endless loop because of a non-finishing plugin. Doesn't affect ACT_SCANNER plugins.
scanner_plugins_timeout
Like plugins_timeout, but for ACT_SCANNER plugins.
safe_checks
Most of the time, openvassd attempts to reproduce an exceptional condition to
determine if the remote services are vulnerable to certain flaws. This includes the
reproduction of buffer overflows or format strings, which may make the remote
server crash. If you set this option to 'yes', openvassd will disable the plugins
which have the potential to crash the remote services, and will at the same time
make several checks rely on the banner of the service tested instead of its
behavior towards a certain input. This reduces false positives and makes openvassd
nicer towards your network, however this may make you miss important
vulnerabilities (as a vulnerability affecting a given service may also affect
another one).
auto_enable_dependencies
OpenVAS plugins use the result of each other to execute their job. For instance, a
plugin which logs into the remote SMB registry will need the results of the plugin
which finds the SMB name of the remote host and the results of the plugin which
attempts to log into the remote host. If you want to only select a subset of the
plugins available, tracking the dependencies can quickly become tiresome. If you
set this option to 'yes', openvassd will automatically enable the plugins that are
depended on.
use_mac_addr
Set this option to 'yes' if you are testing your local network and each local host
has a dynamic IP address (affected by DHCP or BOOTP), and all the tested hosts will
be referred to by their MAC address.
source_iface
Name of the network interface that will be used as the source of connections
established by OpenVAS. The scan won't be launched if the value isn't authorized
according to (sys_)ifaces_allow / (sys_)ifaces_deny if present.
ifaces_allow
Comma-separated list of interfaces names that are authorized as source_iface
values.
ifaces_deny
Comma-separated list of interfaces names that are not authorized as source_iface
values.
sys_ifaces_allow
Like ifaces_allow. Can't be overridden by the client.
sys_ifaces_deny
Like ifaces_deny. Can't be overridden by the client.
hosts_allow
Comma-separated list of the only targets that are authorized to be scanned.
Supports the same syntax as the list targets. Both target hostnames and the address
to which they resolve are checked. Hostnames in hosts_allow list are not resolved
however.
hosts_deny
Comma-separated list of targets that are not authorized to be scanned. Supports the
same syntax as the list targets. Both target hostnames and the address to which
they resolve are checked. Hostnames in hosts_deny list are not resolved however.
sys_hosts_allow
Like hosts_allow. Can't be overridden by the client.
sys_hosts_deny
Like hosts_deny. Can't be overridden by the client.
The other options in this file can usually be redefined by the client.
At log in attempt, openvassd checks that the certificate has been signed by a
recognized authority.
NETWORK USAGE
Bear in mind that OpenVAS can be quite network intensive. Even if the OpenVAS developers
have taken every effort to avoid packet loss (including transparently resending UDP
packets, waiting for data to be received in TCP connections, etc.) so bandwidth use should
always be closely monitored, with current server hardware, bandwidth is usually the
bottleneck in a OpenVAS scan. It might not became too apparent in the final reports,
scanners will still run, holes might be detected, but you will risk to run into false
negatives (i.e. OpenVAS will not report a security hole that is present in a remote host)
Users might need to tune OpenVAS configuration if running the scanner in low bandwidth
conditions (low being 'less bandwidth that the one your hardware system can produce) or
otherwise will get erratic results. There are several parameters that can be modified to
reduce network load:
checks_read_timeout
(Introduced in OpenVAS 0.99.4) The default value is set to 5 seconds, that can
(should) be increased if network bandwidth is low in the openvassd.conf or
openvasrc configuration files. Notice that it is recommended to increase this this
value, if you are running a test outside your LAN (i.e. to Internet hosts through
an Internet connection), to over 10 seconds.
max_hosts
Number of hosts to test at the same time (this value is set by the OpenVAS GUI
client or by .openvasrc) it can be as low as you want it to be (obviously 1 is the
minimum)
max_checks
Number of checks to test at the same time (this value is also set by the OpenVAS
GUI client or by .openvasrc ) it can be as low as you want it to be and it will
also reduce network load and improve performance (obviously 1 is the minimum)
Notice that the OpenVAS scanner will spawn max_hosts * max_checks processes.
Other options might be using the QoS features offered by your server operating
system or your network to improve the bandwidth use.
It is not easy to give a bandwidth estimate for a OpenVAS run, you will probably
need to make your own counts. However, assuming you test 65536 TCP ports. This will
require at least a single packet per port that is at least 40 bytes large. Add 14
bytes for the ethernet header and you will send 65536 * (40 + 14) = 3670016 bytes.
So for just probing all TCP ports we may need a multitude of this as nmap will try
to resend the packets twice if no response is received.
A very rough estimate is that a full scan for UDP, TCP and RPC as well as all NASL
scripts may result in 8 to 32 MB worth of traffic per scanned host. Reducing the
amount of tested part and such will reduce the amount of data to be transferred
significantly.
MORE INFORMATION ABOUT THE OpenVAS PROJECT
The canonical places where you will find more information about the OpenVAS project are:
http://www.openvas.org/ ⟨⟩ (Official site)
http://wald.intevation.org/projects/openvas/ ⟨⟩ (Developers site)
http://bugs.openvas.org ⟨⟩ (Bug Tracker)
AUTHORS
openvassd was forked from nessusd in 2005. Nessusd was written by Renaud Deraison
<deraison@cvs.nessus.org>. Since 2005 the OpenVAS development team improved and extended
the tool.