CVE-2015-8461 in BIND
Summary
by MITRE
Race condition in resolver.c in named in ISC BIND 9.9.8 before 9.9.8-P2 and 9.10.3 before 9.10.3-P2 allows remote attackers to cause a denial of service (INSIST assertion failure and daemon exit) via unspecified vectors.
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Analysis
by VulDB Data Team • 07/01/2022
The vulnerability identified as CVE-2015-8461 represents a critical race condition flaw within the resolver component of ISC BIND versions 9.9.8 prior to 9.9.8-P2 and 9.10.3 prior to 9.10.3-P2. This issue affects the named daemon which serves as the primary DNS server implementation used across internet infrastructure. The race condition manifests in the resolver.c file where concurrent access patterns create unpredictable states that can lead to assertion failures. According to CWE-362, this vulnerability falls under the category of race conditions, which occur when multiple threads or processes access shared resources without proper synchronization mechanisms. The flaw specifically impacts the INSIST assertion mechanism within the BIND resolver, which is designed to catch programming errors and invalid states during runtime operations.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the stability of critical DNS infrastructure. Remote attackers can exploit this condition to trigger assertion failures that cause the named daemon to terminate unexpectedly, resulting in complete denial of service for DNS resolution services. This type of attack directly maps to the ATT&CK technique T1499.004 which describes network disruption attacks targeting DNS services. The vulnerability's exploitation does not require authentication or special privileges, making it particularly dangerous as it can be leveraged by any remote attacker to cause widespread service degradation across networks that rely on affected BIND versions. The daemon exit creates a cascading effect that can impact downstream systems depending on the compromised DNS server for name resolution.
Mitigation strategies for CVE-2015-8461 focus primarily on immediate patching of affected BIND installations to the recommended versions 9.9.8-P2 or 9.10.3-P2 respectively. Organizations should implement comprehensive vulnerability management processes to identify all instances of affected BIND versions across their network infrastructure. System administrators should also consider implementing monitoring solutions that can detect daemon crashes or restarts that may indicate exploitation attempts. The vulnerability highlights the importance of proper synchronization mechanisms in multi-threaded applications and demonstrates how seemingly minor flaws in core infrastructure components can lead to significant operational disruptions. Network segmentation and redundant DNS server configurations can provide additional resilience against such attacks, while regular security audits should verify that all DNS infrastructure components are properly updated and maintained against known vulnerabilities.