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 17:51:12 UTC 2012
Note: This email advisory is provided for your information. The most up
to date advisory information will always be at:
please use this URL for the most up to date advisory information.
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
Internet Systems Consortium (ISC) is providing this notice on an "AS IS"
basis. No warranty or guarantee of any kind is expressed in this notice
and none should be implied. ISC expressly excludes and disclaims any
warranties regarding this notice or materials referred to in this
notice, including, without limitation, any implied warranty of
merchantability, fitness for a particular purpose, absence of hidden
defects, or of non-infringement. Your use or reliance on this notice or
materials referred to in this notice is at your own risk. ISC may change
this notice at any time.
A stand-alone copy or paraphrase of the text of this document that omits
the document URL is an uncontrolled copy. Uncontrolled copies may lack
important information, be out of date, or contain factual errors.
More information about the dhcp-announce