CVE-2012-3817 in BIND
Summary
by MITRE
ISC BIND 9.4.x, 9.5.x, 9.6.x, and 9.7.x before 9.7.6-P2; 9.8.x before 9.8.3-P2; 9.9.x before 9.9.1-P2; and 9.6-ESV before 9.6-ESV-R7-P2, when DNSSEC validation is enabled, does not properly initialize the failing-query cache, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) by sending many queries.
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Analysis
by VulDB Data Team • 03/27/2021
The vulnerability identified as CVE-2012-3817 affects the Internet Systems Consortium BIND DNS server versions across multiple release branches including 9.4.x through 9.7.x, 9.8.x, 9.9.x, and the 9.6-ESV branch. This issue specifically manifests when DNSSEC validation is enabled within the DNS server configuration, creating a critical weakness in the server's handling of query processing. The vulnerability stems from improper initialization of the failing-query cache mechanism, which is designed to track and manage queries that fail during processing. This flaw represents a significant security concern as it directly impacts the availability and stability of DNS services that rely on BIND as their authoritative or recursive server implementation. The affected versions were widely deployed across enterprise networks, internet service providers, and critical infrastructure components, making this vulnerability particularly dangerous in production environments where DNS availability is paramount.
The technical exploitation of this vulnerability occurs through a carefully crafted sequence of DNS queries that trigger the assertion failure within the BIND daemon process. When DNSSEC validation is enabled, the server maintains a cache of failing queries to prevent repeated processing of malformed or problematic requests. However, the improper initialization of this cache structure causes the server to crash when encountering certain query patterns, resulting in an assertion failure that leads to the daemon exiting abruptly. This behavior creates a denial of service condition where legitimate DNS queries cease to be processed, effectively cutting off network access for services dependent on DNS resolution. The flaw is particularly insidious because it requires only a relatively small number of malicious queries to trigger the daemon crash, making it an efficient vector for service disruption attacks. The vulnerability operates at the application layer within the DNS processing pipeline and demonstrates a classic example of improper resource initialization that can lead to system instability.
The operational impact of CVE-2012-3817 extends far beyond simple service disruption, as DNS servers form the backbone of internet infrastructure and network operations. When a BIND server running affected versions experiences the assertion failure and subsequent daemon exit, it creates cascading failures throughout the network ecosystem that depends on that server for name resolution. Organizations may experience complete loss of DNS functionality, leading to widespread service outages for applications, websites, and internal network services that rely on proper DNS resolution. The vulnerability is particularly concerning for recursive DNS servers that serve large numbers of clients, as a single attacker could potentially disrupt services for thousands of end users. Network administrators face the challenge of identifying vulnerable systems, implementing immediate mitigations, and coordinating patches across multiple environments while maintaining service availability during the remediation process.
Organizations should immediately implement mitigations including upgrading to patched versions of BIND that address the failing-query cache initialization issue, specifically versions 9.7.6-P2, 9.8.3-P2, 9.9.1-P2, and 9.6-ESV-R7-P2. The vulnerability aligns with CWE-459, which describes improper initialization of resources, and represents a failure in proper memory management within the DNS processing pipeline. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique involving network denial of service attacks, where adversaries leverage application-level flaws to disrupt services. Additionally, the issue demonstrates characteristics of T1566.002 involving credential access through service exploitation, as compromised DNS servers can be used as stepping stones for further network infiltration. Security teams should also consider implementing query rate limiting and monitoring for unusual query patterns that might indicate exploitation attempts, while ensuring that DNSSEC validation is properly configured and tested in isolation before enabling it in production environments to prevent similar issues from occurring in the future.