The Internet Systems Consortium (ISC) has issued patches to fix several security vulnerabilities in the Berkeley Internet Name Domain (BIND) 9 Domain Name System (DNS) software suite. These vulnerabilities could be exploited to trigger a denial-of-service (DoS) condition. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has warned that a cyber threat actor could leverage these flaws to disrupt services.
Four specific vulnerabilities were identified, each with a CVSS score of 7.5. These include logic errors that cause assertion failures, excessive CPU load from validating DNS messages, slow database processing due to large numbers of resource record types, and server unresponsiveness caused by malicious DNS clients sending many queries over TCP. Successful exploitation could lead to unexpected termination of a named instance, depleted CPU resources, significantly slowed query processing, and an unresponsive server.
The issues have been addressed in BIND 9 versions 9.18.28, 9.20.0, and 9.18.28-S1, which were released earlier this month. So far, there is no evidence that these vulnerabilities have been exploited in the wild. The prompt patching of these flaws is critical to maintaining the security and functionality of affected systems.
This disclosure follows a previous patch by the ISC for another BIND 9 flaw called KeyTrap (CVE-2023-50387), which also had a CVSS score of 7.5. KeyTrap could be exploited to exhaust CPU resources and stall DNS resolvers, leading to a denial-of-service condition. The continued efforts by ISC to address such vulnerabilities highlight the importance of staying current with software updates to protect against potential cyber threats.
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