Rule:

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Sid:
2561

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Summary:
This event is generated when an attempt is made to exploit a vulnerability
associated with rsync.

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Impact:
A successful attack may allow files to be existing files to be overwritten
or new files created on the rsync server.

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Detailed Information:
rsync is used to remote copy files.  A command line option "--backup-dir"
can be used to specify a directory where backup files are to be placed.
There is no validation of the argument supplied to this option to scrutinize
it for proper formatting.  A malicious user can try to overwrite existing
files or create new ones on a vulnerable host by supplying a value to
"--backup-dir" that is relative to the root directory.

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Affected Systems:
Many Unix and Linux distributions running rsync.
See http://www.securityfocus.com/bid/10247 for affected operating systems.

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Attack Scenarios:
An attacker can send a rsync command supplying the -backup-dir option
with a path relative to the root file system, overwriting or creating
new files on the vulnerable host.

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Ease of Attack:
Simple.

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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.
Run the rsync server in a chroot environment.

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Contributors:
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>
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Additional References

CVE:
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0426

Bugtraq:
http://www.securityfocus.com/bid/10247

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