CVE-2012-5166 in BIND
Summary
by MITRE
ISC BIND 9.x before 9.7.6-P4, 9.8.x before 9.8.3-P4, 9.9.x before 9.9.1-P4, and 9.4-ESV and 9.6-ESV before 9.6-ESV-R7-P4 allows remote attackers to cause a denial of service (named daemon hang) via unspecified combinations of resource records.
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Analysis
by VulDB Data Team • 04/14/2021
The vulnerability described in CVE-2012-5166 represents a critical denial of service weakness affecting the Internet Systems Consortium BIND DNS server software across multiple version lines. This vulnerability specifically impacts ISC BIND versions prior to the mentioned patch levels, creating a scenario where remote attackers can manipulate the named daemon process to enter a hung state, effectively rendering the DNS service unavailable to legitimate users. The issue stems from insufficient validation mechanisms within the DNS record processing logic that fails to properly handle certain combinations of resource records, leading to the daemon becoming unresponsive during normal operational conditions.
The technical flaw manifests through the improper handling of resource record combinations during DNS query processing, where the named daemon encounters specific record structures that trigger internal state corruption or infinite loop conditions. This vulnerability operates at the application layer within the DNS server implementation, exploiting weaknesses in the parsing and validation routines that process incoming DNS requests. The unspecified nature of the exact record combinations suggests that the flaw affects multiple record types or configurations that, when processed together, create conditions that cause the daemon to hang rather than properly respond to or reject the malformed requests.
From an operational perspective, this vulnerability presents significant risk to organizations relying on BIND DNS servers for critical infrastructure services. The denial of service condition can be triggered remotely without authentication, making it particularly dangerous as attackers can exploit the vulnerability from outside the network perimeter. The impact extends beyond simple service interruption to potentially disrupting DNS resolution for all clients relying on the affected server, which could cascade into broader network outages affecting email services, web applications, and other internet-dependent systems. The vulnerability affects multiple release branches including the standard versions and the Extended Support Version (ESV) releases, indicating a widespread issue that required patching across the entire product lineage.
The security implications align with CWE-400, which addresses "Uncontrolled Resource Consumption" in software systems, and demonstrates how improper input validation can lead to resource exhaustion scenarios. This vulnerability also maps to ATT&CK technique T1499.004, "Endpoint Denial of Service," as it enables attackers to consume system resources through crafted DNS queries, ultimately causing service disruption. Organizations implementing DNS services using affected BIND versions should prioritize immediate patching to address this vulnerability, as the lack of authentication requirements for exploitation makes it particularly dangerous in production environments. The vulnerability underscores the importance of proper input validation and resource management in critical network infrastructure components, highlighting how seemingly minor implementation flaws can result in significant operational impacts. Security teams should also implement monitoring solutions to detect unusual DNS query patterns that might indicate exploitation attempts, while maintaining awareness of the specific version ranges affected to ensure comprehensive remediation across all impacted systems.