dsniff - password sniffer
dsniff [-c] [-d] [-m] [-n] [-i interface | -p pcapfile] [-s snaplen]
[-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).
-d Enable debugging mode.
-m Enable automatic protocol detection.
-n Do not resolve IP addresses to hostnames.
Specify the interface to listen on.
Rather than processing the contents of packets observed upon the
network process the given PCAP capture file.
Analyze at most the first snaplen bytes of each TCP connection,
rather than the default of 1024.
Load triggers from a services file.
Load triggers from a comma-separated list, specified as
port/proto=service (e.g. 80/tcp=http).
Read sniffed sessions from a savefile created with the -w
Write sniffed sessions to savefile rather than parsing and
printing them out.
Specify a tcpdump(8) filter expression to select traffic to
On a hangup signal dsniff will dump its current trigger table to
Default trigger table
Network protocol magic
arpspoof(8), libnids(3), services(5), magic(5)
Dug Song <email@example.com>
dsniff’s automatic protocol detection feature is based on the classic
file(1) command by Ian Darwin, and shares its historical limitations