CVE-2018-5734

A malformed request can trigger an assertion failure in badcache.c

Description

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. Affects BIND 9.10.5-S1 to 9.10.5-S4, 9.10.6-S1, 9.10.6-S2.

Remediation

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

Workaround:

  • Disabling the SERVFAIL cache with 'servfail-ttl 0;' will prevent taking the code path that leads to the assertion failure.

Category

7.5
CVSS
Severity: High
CVSS 3.0 •
CVSS 2.0 •
EPSS 8.70% Top 10%
Vendor Advisory isc.org
Affected: ISC BIND 9
Published at:
Updated at:

References

Link Tags
https://kb.isc.org/docs/aa-01562 vendor advisory
https://security.netapp.com/advisory/ntap-20180926-0005/ third party advisory
http://www.securityfocus.com/bid/103189 vdb entry third party advisory
http://www.securitytracker.com/id/1040438 vdb entry third party advisory

Frequently Asked Questions

What is the severity of CVE-2018-5734?
CVE-2018-5734 has been scored as a high severity vulnerability.
How to fix CVE-2018-5734?
To fix CVE-2018-5734: 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
Is CVE-2018-5734 being actively exploited in the wild?
It is possible that CVE-2018-5734 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~9% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2018-5734?
CVE-2018-5734 affects ISC BIND 9.
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