dsniff

dsniff [-v] [-c] [-a] [-d] [-m] [-D] [-N] [-P] [-i interface | -p pcapfile] [-s snaplen] [-M magics] [-f services] [-t trigger[,...]] [-r|-w savefile] [expression]

dsniff is a password sniffer which handles FTP, Telnet, SMTP, HTTP, POP, poppass, NNTP, IMAP, SNMP, LDAP, Rlogin, RIP, OSPF, PPTP MS-CHAP, NFS, VRRP, YP/NIS, SOCKS, X11, CVS, IRC, AIM, ICQ, Napster, PostgreSQL, Meeting Maker, Citrix ICA, Symantec pcAnywhere, NAI Sniffer, Microsoft SMB, Oracle SQL*Net, Sybase and Microsoft SQL protocols.

dsniff automatically detects and minimally parses each application protocol, only saving the interesting bits, and uses Berkeley DB as its output file format, only logging unique authentication attempts. Full TCP/IP reassembly is provided by libnids(3).

I wrote dsniff with honest intentions - to audit my own network, and to demonstrate the insecurity of cleartext network protocols. Please do not abuse this software.

-c

Perform half-duplex TCP stream reassembly, to handle asymmetrically routed traffic (such as when using arpspoof(8) to intercept client traffic bound for the local gateway).

-v

Verbose. Show banners.

-a

Show all results. Otherwise dsniff tries not to show to many duplicates.

-d

Enable debugging mode.

-m

Force protocol detection/DPI also on known services. For example, -m will detect SSH _and_ HTTPS on port 443.

-N

Resolve IP addresses to hostnames.

-P

Enable promisc mode.

-C

Force color output even if not a tty.

-D

Disable DPI. Only decode known services (DPI is enabled by default on unknown ports).

-i interface

Specify the interface to listen on.

-p pcapfile

Rather than processing the contents of packets observed upon the network process the given PCAP capture file.

-s snaplen

Analyze at most the first snaplen bytes of each TCP connection, rather than the default of 1024.

-f services

Load triggers from a services file. Default is to use internal.

-M magicfile

Load magics from file. Default is to use internal. Can not be used with -t.

-t trigger[,...]

Load triggers from a comma-separated list, specified as port/proto=service (e.g. 80/tcp=http).

-r savefile

Read sniffed sessions from a savefile created with the -w option.

-w file

Write sniffed sessions to savefile rather than parsing and printing them out.

expression

Specify a tcpdump(8) filter expression to select traffic to sniff.

On a hangup signal dsniff will dump its current trigger table to dsniff.services.

/usr/share/dsniff/dsniff.services

Default trigger table

/usr/share/dsniff/dsniff.magic

Network protocol magic

arpspoof(8), libnids(3), services(5), magic(5)

Dug Song <dugsong@monkey.org>

dsniff's automatic protocol detection feature is based on the classic file(1) command by Ian Darwin, and shares its historical limitations and bugs.