Rule:

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Sid:
2093

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Summary:
This event is generated when an attempt is made to exploit a known vulnerability in xdrmem_getbytes used by XDR in RPC portmap services.

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Impact:
System compromise, denial of service, execution of arbitrary code, information disclosure.

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Detailed Information:
A vulnerability exists in various implementations of external data representation (XDR) libraries. An integer overflow in a component (xdrmem_getbytes) used by XDR can lead to a buffer overflow.

The XDR libraries are widely used by multiple vendors to provide a framework for data transmission across networks. This is most commonly used in RPC implementations.

A specially crafted rpc request can lead to remote system compromise and super user access to the target host. Additionally, a denial of service and execution of arbitrary code with the privilege of the super user is also possible.

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Affected Systems:
Multiple vendors including all those using:
Sun Microsystems Network Services Library (libnsl)
GNU C library with sunrpc (glibc)
BSD-derived libraries with XDR/RPC routines (libc)

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Attack Scenarios:
The attacker needs to send a specially crafted rpc request to the target
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:
Apply the appropriate vendor supplied patches.

Upgrade the vendor libraries to the latest non-affected versions. Any statically linked binaries and applications must be recompiled and restarted after the upgrade.

Disallow all RPC requests from external sources and use a firewall to block access to RPC ports from outside the LAN.

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

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Additional References:

CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0028

CERT:
http://www.cert.org/advisories/CA-2003-10.html
http://www.kb.cert.org/vuls/id/516825
http://www.kb.cert.org/vuls/id/192995

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