CVE-2011-2465 in BIND
Summary
by MITRE
Unspecified vulnerability in ISC BIND 9 9.8.0, 9.8.0-P1, 9.8.0-P2, and 9.8.1b1, when recursion is enabled and the Response Policy Zone (RPZ) contains DNAME or certain CNAME records, allows remote attackers to cause a denial of service (named daemon crash) via an unspecified query.
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Analysis
by VulDB Data Team • 12/28/2024
The vulnerability identified as CVE-2011-2465 represents a critical denial of service flaw within the Internet Systems Consortium BIND DNS server software. This vulnerability specifically affects versions 9.8.0 through 9.8.1b1 and manifests when the recursive DNS server is configured with Response Policy Zone functionality enabled. The flaw occurs under specific conditions where the RPZ contains either DNAME records or particular CNAME records, creating a scenario that can be exploited by remote attackers to crash the named daemon process. The vulnerability demonstrates the inherent complexity of DNS server implementations and their susceptibility to crafted queries that can trigger memory management issues or processing errors within the recursive resolution engine.
The technical root cause of this vulnerability stems from inadequate input validation and error handling within the BIND recursive resolver when processing certain DNS record types within RPZ configurations. When a recursive server encounters a query that triggers the processing of DNAME or specific CNAME records within an RPZ, the internal data structures and state management mechanisms fail to properly handle the edge case scenarios. This typically results in memory corruption or stack overflow conditions that cause the named daemon to terminate unexpectedly. The vulnerability operates at the application layer of the network stack and requires no authentication or privileged access to exploit, making it particularly dangerous in production environments where DNS servers serve as critical infrastructure components.
The operational impact of CVE-2011-2465 extends beyond simple service disruption to potentially compromise the availability of critical network services. Organizations relying on BIND servers for recursive resolution may experience complete DNS service outages until the named daemon is manually restarted, leading to cascading failures across dependent systems and applications. The vulnerability's exploitation can occur through any legitimate DNS client that sends queries to the affected server, making it difficult to detect and mitigate. This type of vulnerability aligns with CWE-121, heap-based buffer overflow, and CWE-122, stack-based buffer overflow, as the underlying issue involves improper handling of dynamic memory allocation during DNS record processing. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1499.004, Network Denial of Service, and represents a classic example of how DNS infrastructure can be targeted for availability attacks.
Mitigation strategies for CVE-2011-2465 primarily involve immediate software updates to patched versions of BIND 9.8.1 or later, which contain the necessary fixes to properly handle DNAME and CNAME records within RPZ configurations. Organizations should also consider implementing temporary workarounds such as disabling RPZ functionality or restricting recursive queries to trusted clients only. Network monitoring should be enhanced to detect unusual patterns of DNS queries that might indicate exploitation attempts, and incident response procedures should be updated to include rapid recovery protocols for DNS service disruptions. Security teams should also review their BIND configurations to ensure that RPZ zones do not contain the problematic record types that trigger this vulnerability, as the fix addresses the root cause rather than merely providing a workaround for specific scenarios.