ISC fixed high-severity flaws in the BIND DNS software

Pierluigi Paganini September 24, 2022

The Internet Systems Consortium (ISC) fixed six remotely exploitable vulnerabilities in the BIND DNS software.

The Internet Systems Consortium (ISC) this week released security patches to address six remotely exploitable vulnerabilities in BIND DNS software.

Four out of six flaws, all denial-of-service (DoS) issue, have been rated as ‘high’ severity.

One of the issues, tracked as CVE-2022-2906 (CVSS score 7.5), is a memory leak in code handling Diffie-Hellman key exchange via TKEY RRs (OpenSSL 3.0.0+ only).

“Changes between OpenSSL 1.x and OpenSSL 3.0 expose a flaw in named that causes a small memory leak in key processing when using TKEY records in Diffie-Hellman mode with OpenSSL 3.0.0 and later versions.” reads the advisory published by ISC. “An attacker can leverage this flaw to gradually erode available memory to the point where named crashes for lack of resources. Upon restart the attacker would have to begin again, but nevertheless there is the potential to deny service.”


Another flaw, tracked as CVE-2022-38177, is a memory leak in ECDSA DNSSEC verification code. An attacker can trigger the vulnerability through a signature length mismatch.

A third issue, tracked as CVE-2022-3080, may cause the crash of the BIND 9 resolver under certain conditions, when specially crafted queries are sent to the resolver.

“BIND 9 resolver can crash when stale cache and stale answers are enabled, option stale-answer-client-timeout is set to 0 and there is a stale CNAME in the cache for an incoming query. Impact: By sending specific queries to the resolver, an attacker can cause named to crash.” reads the advisory.

The fourth high severity vulnerability, tracked as CVE-2022-38178 is a memory leak in EdDSA DNSSEC verification code.

The good news is that ISC is not aware of attacks in the wild exploiting the above vulnerabilities.

The US Cybersecurity and Infrastructure Security Agency (CISA) also published a security advisory to warn of the vulnerabilities.

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Pierluigi Paganini

(SecurityAffairs – hacking, BIND DNS)

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