CVE-2010-0097: BIND 9 DNSSEC validation code could cause bogus NXDOMAIN responses

CVE: CVE-2010-0097

CERT: VU#360341

Posting Date: 19 Jan 2010

Program Impacted: BIND

Versions Affected: 9.0.x, 9.1.x, 9.2.x, 9.3.x, 9.4.0 -> 9.4.3-P4, 9.5.0 -> 9.5.2-P1, 9.6.0 -> 9.6.1-P2

Severity: Low

Exploitable: Remotely

Description

There was an error in the DNSSEC NSEC/NSEC3 validation code that could cause bogus NXDOMAIN responses (that is, NXDOMAIN responses for records proven by NSEC or NSEC3 to exist) to be cached as if they had validated correctly, so that future queries to the resolver would return the bogus NXDOMAIN with the AD flag set.

Impact

This problem affects all DNSSEC-validating resolvers. It would be difficult to exploit due to other existing protections against cache poisoning (including transaction ID and source port randomization), but it could impair the ability of DNSSEC to protect against a denial-of-service attack on a secure zone.

Workarounds: None. Administrators need to upgrade to one of the versions detailed below.

Active Exploits: None known at this time.

Solution  

Upgrade BIND to one of the following: 9.4.3-P5, 9.5.2-P2 or 9.6.1-P3. There are no fixes available for BIND versions 9.0 through 9.3, as those releases are at End of Life. Note for BIND 9.7 beta-testers: pre-releases of 9.7.0 are vulnerable. Upcoming releases will include these patches.

Related Documents

See our BIND 9 Security Vulnerability Matrix for a complete listing of Security Vulnerabilities and versions affected.

Do you still have questions? Questions regarding this advisory should go to security-officer@isc.org.

ISC Security Vulnerability Disclosure Policy: Details of our current security advisory policy and practice can be found in our Software Defect and Security Vulnerability Disclosure Policy.

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