BIND 9 Memory Exhaustion
| Published / (Updated)||Credit
|2013-03-28 / 2013-03-29
|CVSS Base Score
CVE-2013-2266: A Maliciously Crafted Regular Expression Can Cause Memory Exhaustion in named
Author: ISC Support Reference Number: AA-00871 Views: 5456 Created: 2013-02-26 02:57 Last Updated: 2013-03-26 15:56 0
A critical defect in BIND 9 allows an attacker to cause excessive memory consumption in named or other programs linked
Document Version: 2.0
Posting date: 26 March 2013
Program Impacted: BIND
Versions affected: "Unix" versions of BIND 9.7.x, 9.8.0 -> 9.8.5b1, 9.9.0 -> 9.9.3b1. (Windows
versions are not affected. Versions of BIND 9 prior to BIND 9.7.0 (including BIND 9.6-ESV) are not affected. BIND 10 is
A flaw in a library used by BIND 9.7, 9.8, and 9.9, when compiled on Unix and related operating systems, allows an
attacker to deliberately cause excessive memory consumption by the named process, potentially resulting in exhaustion of
memory resources on the affected server. This condition can crash BIND 9 and will likely severely affect operation of
other programs running on the same machine.
Please Note: Versions of BIND 9.7 are beyond their "end of life" (EOL) and no longer receive testing or
security fixes from ISC. However, the re-compilation method described in the "Workarounds" section of this
document will prevent exploitation in BIND 9.7 as well as in currently supported versions.
For current information on which versions are actively supported, please see http://www.isc.org/software/bind/versions.
Additional information is available in the CVE-2013-2266 FAQ and Supplemental Information article in the ISC Knowledge
Intentional exploitation of this condition can cause denial of service in all authoritative and recursive nameservers
running affected versions of BIND 9 [all versions of BIND 9.7, BIND 9.8.0 through 9.8.5b1 (inclusive) and BIND 9.9.0
through BIND 9.9.3b1 (inclusive)]. Additionally, other services which run on the same physical machine as an affected
BIND server could be compromised as well through exhaustion of system memory.
Programs using the libdns library from affected versions of BIND are also potentially vulnerable to exploitation of this
bug if they can be forced to accept input which triggers the condition. Tools which are linked against libdns (e.g.
dig) should also be rebuilt or upgraded, even if named is not being used.
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
Patched versions are available (see the "Solutions:" section below) or operators can prevent exploitation of
this bug in any affected version of BIND 9 by compiling without regular expression support.
Compilation without regular expression support:
BIND 9.7 (all versions), BIND 9.8 (9.8.0 through 9.8.5b1), and BIND 9.9 (9.9.0 through 9.9.3b1) can be rendered
completely safe from this bug by re-compiling the source with regular expression support disabled. In order to disable
inclusion of regular expression support:
After configuring BIND features as desired using the configure script in the top level source directory, manually
edit the "config.h" header file that was produced by the configure script.
Locate the line that reads "#define HAVE_REGEX_H 1" and replace the contents of that line with
Run "make clean" to remove any previously compiled object files from the BIND 9 source directory, then
proceed to make and install BIND normally.
No known active exploits.
Compile BIND 9 without regular expression support as described in the "Workarounds" section of this advisory
or upgrade to the patched release most closely related to your current version of BIND. These can be downloaded from
BIND 9 version 9.8.4-P2
BIND 9 version 9.9.2-P2
Acknowledgements: ISC would like to thank Matthew Horsfall of Dyn, Inc. for discovering this bug and bringing it to our
See this note in TXT Version