CVE-2018-5734: A malformed request can trigger an assertion failure in badcache.c
- Updated on 28 Feb 2018
- 3 minutes to read
28 Feb 2018
9.10.5-S1 to 9.10.5-S4, 9.10.6-S1, 9.10.6-S2
While handling a particular type of malformed packet BIND erroneously selects a SERVFAIL rcode instead of a FORMERR rcode. If the receiving view has the SERVFAIL cache feature enabled, this can trigger an assertion failure in badcache.c when the request doesn't contain all of the expected information.
Servers running the affected versions (9.10.5-S1 to 9.10.5-S4, 9.10.6-S1, and 9.10.6-S2) are vulnerable if they allow recursion, unless the SERVFAIL cache is disabled for the receiving view.
CVSS Score: 7.5
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Disabling the SERVFAIL cache with 'servfail-ttl 0;' will prevent taking the code path that leads to the assertion failure.
No known active exploits.
Solution: Upgrade to the patched release.
- No publicly released versions of BIND are affected
BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers.
- BIND 9 version 9.10.6-S3
Document Revision History: 1.0 Advance Notification 20 February, 2018 2.0 Public Disclosure 28 February, 2018
See our BIND9 Security Vulnerability Matrix at https://kb.isc.org/article/AA-00913 for a complete listing of Security Vulnerabilities and versions affected.
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Note: ISC patches only currently supported versions. When possible we indicate EOL versions affected. (For current information on which versions are actively supported, please see http://www.isc.org/downloads/).
ISC Security Vulnerability Disclosure Policy: Details of our current security advisory policy and practice can be found here: https://kb.isc.org/article/AA-00861/164/ISC-Software-Defect-and-Security-Vulnerability-Disclosure-Policy.html
This Knowledge Base article https://kb.isc.org/article/AA-01562 is the complete and official security advisory document.
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