Rule: 

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Sid: 326

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Summary: 
This event is generated when a remote command execution exploit against a finger daemon is attempted.

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Impact: 
Serious. The attacker may be presented with the opportunity to run a command of his choice on the target UNIX system

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Detailed Information:
This event is generated when a specific attack against a vulnerable version of finger daemon is detected. 

The Finger daemon is used to provide information about users on a UNIX system. It used to be installed and enabled by default on most UNIX/Linux systems. The attack may allow an attacker to execute a command remotely on a target system with the privileges of the user running the "finger" daemon. The user is usually defined in the /etc/inetd.conf file and is commonly designated as "nobody".

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Attack Scenarios:  
An attacker may try the attack and then executes a command to download a backdoor to the target system. He then connects to the system and may attempt to escalate his privileges by exploiting a local SUID application to gain "root" privileges.

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

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False Positives: 
None Known

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False Negatives: 
None Known

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Corrective Action: 
Disable the finger daemon or limit the addresses that can access the service via firewall or TCP wrappers.

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Contributors: 
Original rule written by Max Vision <vision@whitehats.com>
Snort documentation contributed by Anton Chuvakin <http://www.chuvakin.org>
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

Arachnids:
http://www.whitehats.com/info/IDS379

Bugtraq:
http://online.securityfocus.com/bid/974

CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-1999-0150

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