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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2013.0451 CVE-2013-2494: A Vulnerability in libdns Could Cause Excessive Memory Use in ISC DHCP 4.2 2 April 2013 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: DHCP Operating System: UNIX variants (UNIX, Linux, OSX) Windows Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2013-2494 Original Bulletin: https://kb.isc.org/article/AA-00880/ - --------------------------BEGIN INCLUDED TEXT-------------------- CVE-2013-2494: A Vulnerability in libdns Could Cause Excessive Memory Use in ISC DHCP 4.2 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. CVE: CVE-2013-2494 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. Severity: Low Exploitable: From adjacent networks Description: Exploitation of a memory exhaustion bug in libdns is theoretically possible in ISC DHCP 4.2, which uses the library from BIND 9 for Dynamic DNS. 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 defect. Impact: 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: http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=(AV:N/AC:H/Au:S/C:N/I:N/A:C) Workarounds: None. (Or do we want to mention that you can change the build process for the BIND libraries?) Active exploits: No known active exploits. Solution: 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 Related Documents: Japanese Translation: [planned] Spanish Translation: [planned] German Translation: [planned] Portugese Translation: [planned] If you'd like more information on our Forum or product support please visit www.isc.org/support. Do you still have questions? Questions regarding this advisory should go to security-officer@isc.org Note: ISC patches only currently supported versions. When possible we indicate EOL versions affected. 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 This Knowledge Base article https://kb.isc.org/article/AA-00880 is the complete and official security advisory document. 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Uncontrolled copies may lack important information, be out of date, or contain factual errors. © 2001-2013 Internet Systems Consortium - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBUVoxeu4yVqjM2NGpAQJjbg/+OnwQ6Yp94F8+E7cPEmhFLFSOJYeWhbR9 nQCRy9GkfZmJ8UhlW7nKgFj6SlyNQb9knMq6Wdh3jtcB0SQOl4QC8Vs8FdACmT+O zPrlFFgcI+okXkk7te0ZLZAUX/AFIanvnuJJASbxyS/4fUjw4zWfJBRIq4SY0ad4 wEYA7FnX/F+emf3Xx/Xvosx35+grzynNTEmwgeMucmY45WCslJOqqjxrqjbRW771 SlNlDTbTSCrTisAnqaq6xxMEeACakaioP0l6tgIxzz8KGSPKu++GlfK6zrsSOBfr lIko6uqEZx6F28B/tXgG2TtJ+0Vb9hQPkgm41DZMZALKqIDaEbZUcE1YiOpuVQZB 9iiAaCX9PcY9lULFyx8qlqfUqu6cigZN4DwVkgtXVDcF7rjcvi1WhIvEzQlJTga4 PbljSC8W2h2LJZaSFwatLP1xXpZZJUHJ07rTwmMS10RgpqtJyQPDINgdBqUClF+V py5adpMt7/ha81Mp6R1ppiuqKAXsDAqQVW1kS3by2j8xTS/prXtggT4nAoEbVb/r 41BK3lIc2kSolJgO+mEVDYjGQeBHKVCSfQOJlbBrTohQcAArYaW3BDO4Bu61zUkR IDfKCX6GS8HxqTGVmI4ypiNoK9RfHBi9E4azqpRT0prYxvA0PFMPdzg9z7tX5SF/ ZLJAswPg818= =Vaxk -----END PGP SIGNATURE-----