Rule:

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Sid:
2391

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Summary:
This event is generated when an attempt is made to exploit a buffer 
overflow vulnerability associated with WuFtpd APPE command.

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Impact:
Remote access.  A successful attack may permit the remote execution of 
arbitrary commands with system privileges.

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Detailed Information:
WuFtpd is an FTP server based on BSD ftpd. A vulnerability exists 
with the APPE command that can cause a buffer overflow and permit the 
execution of arbitrary commands with system privileges. The buffer 
overflow can be caused by supplying an overly long argument to the APPE 
command.

The issue exists in the realpath() function. It is possible for an
attacker to send malformed data to the realpath() function that will
cause the overflow condition to occur.

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Affected Systems:
	Multiple systems using affected C libraries, libc

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Attack Scenarios:
An attacker can use one of the publicly available exploit scripts to
cause the overflow to occur.

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Ease of Attack:
Simple.  Many exploits exist.

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False Positives:
None Known.

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False Negatives:
None Known.

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Corrective Action:
Upgrade to the latest non-affected version of the software.

Use scp as an alternative to ftp

Disallow ftp access to internal resources from external sources

Recompile binaries statically linked to the system libc implementation

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Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com> 
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

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