Rule:

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Sid:
1331

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Summary:
Attempted uname command access via web

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Impact:
Attempt to gain information on the host operating system using the uname
command.

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Detailed Information:
This is an attempt to gain intelligence about the operating system being
used on a webserver. uname is a UNIX command that will return
information about the operating system, the machine's architecture, the
processor architecture and the version level of the software being used.
This information is valuable to an attacker who can use it to plan
further attacks based on possible vulnerabilities in the machine's
operating system.

Using "uname -a", the attackers might be able to gain accurate
intelligence on the web server platform. The rule looks for the "uname"
command in the URL part of the client to web server connection and does
not indicate whether the command was actually successful in showing the
system information. The presence of the "uname" command in the URL
indicates that an attacker attempted to trick the web server into
executing system commands in non-interactive mode i.e. without a valid
shell session. Another case when this rule might trigger is unencrypted
HTTP tunneling connection to the server.

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Attack Scenarios:
The attacker can make a standard HTTP request that contains 'uname' in
the URI which can then return the machine's operating system environment
architecture.

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Ease of Attack:
Simple HTTP request.

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False Positives:
None Known

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False Negatives:
None Known

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Corrective Action:

Webservers should not be allowed to view or execute files and binaries
outside of it's designated web root or cgi-bin. This command may also be
requested on a command line should the attacker gain access to the machine. 

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Contributors:
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>
Additional information from Anton Chuvakin <http://www.chuvakin.org>

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Additional References:

man uname

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