CVE-2018-5734: A malformed request can trigger an assertion failure in badcache.c
Document version: 2.0
Posting date: 28 Feb 2018
Program impacted: BIND
Versions affected: 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.
Active exploits: 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 9 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 BIND 9 Security Vulnerability Matrix for a complete listing of Security Vulnerabilities and versions affected.
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ISC patches only currently supported versions. When possible we indicate EOL versions affected. (For current information on which versions are actively supported, please see https://www.isc.org/downloads/).
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Details of our current security advisory policy and practice can be found in the ISC Software Defect and Security Vulnerability Disclosure Policy.
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