ISC Security Advisory: An Error in the Handling of Malformed Client Identifiers can Cause a Denial-of-Service Condition in Affected Servers
cathya at isc.org
Tue Jul 24 17:52:34 UTC 2012
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Title: An error in the handling of malformed client identifiers can
cause a denial-of-service condition in affected servers.
Document Version: 2.0
Posting date: 24 Jul 2012
Program Impacted: DHCP
Versions affected: All versions of 4.2 (including 4.2.x-Px) to 4.2.4;
4.1-ESV through 4.1-ESV-R5; 4.1.2, 4.1.2-P1
Exploitable: Locally - From adjacent networks
An error in the handling of malformed client identifiers can cause a
DHCP server running affected versions (see "Impact") to enter a state
where further client requests are not processed and the server process
loops endlessly, consuming all available CPU cycles.
Under normal circumstances this condition should not be triggered, but a
non-conforming or malicious client could deliberately trigger it in a
vulnerable server. In order to exploit this condition an attacker must
be able to send requests to the DHCP server .
Causes the server process to loop endlessly, resulting in a denial of
service. NOTE: ISC DHCP 3.0.x and ISC DHCP 4.0.x are EOL and have not
been tested for this vulnerability. Versions of ISC DHCP that are
vulnerable to CVE-2010-2156 (including 4.1.0 through 4.1.1-P1) can be
expected to terminate unexpectedly instead of looping endlessly.
CVSS Score: 6.1
CVSS Equation: (AV:A/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
None known at this time.
Upgrade affected systems to DHCP 4.1-ESV-R6 or DHCP 4.2.4-P1
DHCP 4.2.4-P1 is available from www.isc.org/downloads/all
DHCP 4.1-ESV-R6 is available from www.isc.org/downloads/all
Markus Hietava of Codenomicon CROSS project for finding the
vulnerability, and CERT-FI for vulnerability coordination.
Document Revision History:
1.0 - 03 July 2012 Phase I notified
1.1 - 13 July 2012 HOLD notice sent to Phase 1 regarding new CVE
being added and new public release date
1.2 - 23 July 2012 Phase 2 & 3 notified
2.0 - 24 July 2012 Phase 4-Public released
Do you have Questions? Questions regarding this advisory should go to
security-officer at isc.org.
ISC Security Vulnerability Disclosure Policy: Details of our current
security advisory policy and practice can be found here:
German Translation: https://kb.isc.org/article/AA-00739
Spanish Translation: https://kb.isc.org/article/AA-00747
Japanese Translation: https://kb.isc.org/article/AA-00755
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