CVE-2012-5688 in BIND
Summary
by MITRE
ISC BIND 9.8.x before 9.8.4-P1 and 9.9.x before 9.9.2-P1, when DNS64 is enabled, allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a crafted query.
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Analysis
by VulDB Data Team • 04/19/2021
The vulnerability identified as CVE-2012-5688 represents a critical denial of service flaw in ISC BIND DNS server software that affects versions prior to 9.8.4-P1 and 9.9.2-P1. This issue specifically manifests when DNS64 functionality is enabled, which is a DNS protocol extension designed to enable IPv6-only clients to communicate with IPv4 servers through DNS name synthesis. The vulnerability stems from an assertion failure within the DNS64 implementation that occurs when processing specially crafted DNS queries, leading to the complete termination of the BIND daemon process.
The technical flaw resides in the improper handling of malformed DNS queries within the DNS64 subsystem of BIND. When a remote attacker crafts specific DNS query packets that exploit edge cases in the DNS64 processing logic, the software encounters an assertion that fails, causing an immediate crash of the named daemon process. This assertion failure represents a classic software reliability issue where insufficient input validation leads to program termination rather than graceful error handling. The vulnerability maps to CWE-617, which describes reachable assertions that can be triggered by external input, and demonstrates poor error handling practices that violate fundamental security principles.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on BIND DNS servers with DNS64 enabled. The remote nature of the attack means that any system with DNS64 functionality enabled is potentially vulnerable to exploitation without requiring authentication or local access. The impact extends beyond simple service disruption as the daemon crash can lead to cascading failures in network infrastructure, particularly in environments where DNS resolution is critical for internal operations. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks targeting DNS services, and represents a common pattern of exploiting protocol implementation flaws to achieve service disruption.
Organizations should immediately implement mitigations including upgrading to BIND versions 9.8.4-P1 or 9.9.2-P1, which contain the necessary patches to address the assertion failure. Additionally, administrators should consider disabling DNS64 functionality if it is not actively required, as this eliminates the attack surface entirely. Network segmentation and monitoring should be enhanced to detect unusual patterns of DNS query traffic that might indicate exploitation attempts. The vulnerability demonstrates the importance of thorough testing of protocol extensions and the critical need for robust error handling in security-critical software components, particularly those handling external network input. Security teams should also implement automated patch management processes to ensure rapid deployment of security updates across all DNS infrastructure components.