ISC DHCP Server Halt

Summary:

Two issues have been found in DHCP that could allow an attacker to cause the server to halt.

CVE:

CVE-2011-2748

Document Version:

1.1

Posting date:

10 Aug 2011

Program Impacted:

DHCP

Versions affected:

3.1.0 through 3.1-ESV-R1 (R2 never released) 4.0 all versions (EOL) 4.1.0 through 4.1.2rc1 4.1-ESV through 4.1-ESV-R3b1 4.2.0 through 4.2.2rc1 All End-of-Life versions of DHCP server are likely to be affected and ISC recommends upgrading to supported versions.

Severity:

High

Exploitable:

Remotely

Description:

A pair of defects cause the server to halt upon processing certain packets. The patch is to properly discard or process those packets.

Document ID: CVE-2011-2748, CVE-2011-2749

CVSS Score: 7.8

CVSS Equation: (AV:N/AC:L/Au:N/C:N/I:N/A:C)

For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit: http://nvd.nist.gov/cvww.cfm?calculator&adv&version=vector=(AV:N/AC:L/Au:N/C:N/I:N/A:C)

Workarounds:

Limiting DHCP and Bootp packets to only within your administrative domain will limit exposure.

Active exploits:

ISC received a report for one of the flaws and discovered the other during testing. No public exploits using these bugs are known.

Solution:

Upgrade to: 3.1-ESV-R3, 4.1-ESV-R3 or 4.2.2

Please note that this is the last update to 3.1-ESV as it will be End-of-Life after this release.

Download these versions from https://www.isc.org/downloads/all

Acknowledgment:
Found by David Zych at University of Illinois

Document Revision History

1.0 27 July 2011 - Phase 1 disclosure

1.1 09 August 2011 - Phase 2 and 3 disclosures

Related Document:

Do you have Questions? Questions regarding this advisory should go to security-officer@isc.org.

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ISC Security Vulnerability Disclosure Policy: Details of our current security advisory policy and practice can be found here: https://www.isc.org/security-vulnerability-disclosure-policy

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