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             AUSCERT External Security Bulletin Redistribution

         DHCP May Crash After Processing a DHCPv6 Decline Message
                              28 January 2011


        AusCERT Security Bulletin Summary

Product:           ISC DHCP 4.0.x through 4.2.x
Publisher:         Internet Systems Consortium
Operating System:  Linux variants
                   BSD variants
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2011-0413  

Original Bulletin: 

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Internet Systems Consortium Security Advisory

This ISC Security Advisory is provided as part of our Phased Disclosure

Title: DHCP May Crash After Processing a DHCPv6 Decline Message

CVE# 2011-0413

VU# 686084

CVSS: 6.2

Posting date: 2011-01-21 (Advanced notice)

Program Impacted: DHCP

Versions affected: 4.0.x-4.2.x

Severity: moderate

Exploitable: remotely

Description and Impact:

When the DHCPv6 server code processes a message for an address that was
previously declined and internally tagged as abandoned it can trigger an
assert failure resulting in the server crashing. This could be used to
crash DHCPv6 servers remotely. This issue only affects DHCPv6 servers.
DHCPv4 servers are unaffected.

Workarounds: No direct workaround.

Exposure to the vulnerability can be limited by a review of the filters
and access to the DHCP server. It is highly recommended to limit access
to those devices which require DHCP server, management access, and
systems monitoring.

Active exploits: None known.

Solution: Upgrade to 4.1.2-P1, 4.1-ESV-R1, or 4.2.1b1.

Questions regarding this advisory or ISC's Support services should be
sent to dhcp-bugs@isc.org

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