ISC Security Advisory: CVE-2013-2494: A Vulnerability in libdns Could Cause Excessive Memory Use in ISC DHCP 4.2
ewinstead at isc.org
Tue Mar 26 16:13:58 UTC 2013
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up to date advisory information will always be at:
https://kb.isc.org/article/AA-00880 please use this URL for the
most up to date advisory information.
A memory exhaustion bug has been discovered in libdns, which is
used by ISC DHCP 4.2. Theoretically this could be exploited to
cause memory exhaustion in ISC DHCP 4.2.
Document Version: 2.0
Posting date: 26 March 2013
Program Impacted: ISC DHCP
Versions affected: 4.2.0 -> 4.2.5. ISC DHCP versions prior to 4.2.0
(including 4.1-ESV) are not affected.
Exploitable: From adjacent networks
Exploitation of a memory exhaustion bug in libdns is theoretically
possible in ISC DHCP 4.2, which uses the library from BIND 9 for
Unlike vulnerabilities which can be exercised by a machine
impersonating a malicious client, exploitation of this vulnerability
is complex and requires either controlling a nameserver with
whom the DHCP server process is communicating or successfully
spoofing traffic to appear as such. These preconditions result
in a CVSS severity of "Low", but operators using vulnerable
versions of DHCP 4.2 are nevertheless recommended to upgrade to
DHCP 4.2.5-P1, which prevents exploitation of the libdns library
Servers which are targeted by a successful attack will exhaust
all memory available to the server process, which is likely to
crash the DHCP server and may affect other processes running on
the same physical machine when system memory is exhausted.
CVSS Score: 4.9
CVSS Equation: (AV:N/AC:H/Au:S/C:N/I:N/A:C)
For more information on the Common Vulnerability Scoring System and
to obtain your specific environmental score please visit:
No known active exploits.
Upgrade to DHCP 4.2.5-P1
Document Revision History:
1.0 Phase One - Advance Notification, 18 March 2013
1.2 Phase Two & Three Notification, 25 March 2013
2.0 Public notification, 26 March 2013
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