[Snort-sigs] SID 327

Anton Chuvakin anton at ...1177...
Thu Jan 30 20:37:05 EST 2003

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alert tcp $EXTERNAL_NET any -> $HOME_NET 79 (msg:"FINGER remote
command pipe execution attempt"; flow:to_server,established;
content:"|7c|"; reference:cve,CVE-1999-0152; reference:bugtraq,2220;
reference:arachnids,380; classtype:attempted-user; sid:327; rev:5;)

Sid: 327


Summary: A remote command execution exploit against a finger daemon


Impact: attacker will run a command of his choice on the target UNIX

Detailed Information:

The signature is triggerred when a specific attack against a vulnerable
version of finger daemon is detected. Finger daemon is used to provide
information about the UNIX system users. It used to be installed and
enabled by default on most UNIX/Linux systems, but is more often disabled
nowadays. The attack allows running a command remotely on a target system
with the privileges of a "finger" user. The user is usually defined in the
/etc/inetd.conf file. The user "nobody" is commonly used for this purpose
on UNIX systems.


Attack Scenarios: an attacker runs an attack and executes a command to
download a backdoor to the target system. He then connects to a
systems and exploits local SUID application to gain "root" privileges.


Ease of Attack: very simple, no exploit software is required, just a
specially formatted finger query


False Positives: not known

False Negatives: not known


Corrective Action: disable fingerd daemon, patch to a non-vulnerable
version or limit the addresses that can access the service via firewall or
TCP wrappers.

Contributors: Anton Chuvakin <http://www.chuvakin.org>

Additional References:


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