CVE-2011-1910 in BIND
Summary
by MITRE
Off-by-one error in named in ISC BIND 9.x before 9.7.3-P1, 9.8.x before 9.8.0-P2, 9.4-ESV before 9.4-ESV-R4-P1, and 9.6-ESV before 9.6-ESV-R4-P1 allows remote DNS servers to cause a denial of service (assertion failure and daemon exit) via a negative response containing large RRSIG RRsets.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2011-1910 represents a critical off-by-one error within the Internet Systems Consortium BIND DNS server software that affects multiple version branches including 9.x before 9.7.3-P1, 9.8.x before 9.8.0-P2, 9.4-ESV before 9.4-ESV-R4-P1, and 9.6-ESV before 9.6-ESV-R4-P1. This flaw exists in the handling of DNS responses and specifically targets the processing of RRSIG resource record sets within negative DNS responses. The issue manifests when a remote DNS server sends a maliciously crafted response containing large RRSIG RRsets that trigger an assertion failure within the named daemon process.
The technical implementation of this vulnerability stems from improper boundary checking during the processing of DNS response data structures. When BIND encounters a negative DNS response containing oversized RRSIG records, the off-by-one error causes the software to access memory locations beyond the allocated buffer boundaries. This memory corruption results in an assertion failure that terminates the named daemon process, effectively causing a denial of service condition that impacts legitimate DNS resolution services. The vulnerability operates at the application layer within the DNS server software stack and requires no authentication or privileged access to exploit.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged by attackers to repeatedly cause daemon exits and restarts, creating sustained availability issues for DNS infrastructure. Network administrators face the challenge of maintaining DNS service availability when malicious actors can trigger these assertion failures through crafted DNS responses. The vulnerability affects both primary and secondary DNS servers that process negative responses, making it particularly dangerous for authoritative DNS operators who must maintain high availability for their services. The attack vector involves sending specially crafted DNS responses that contain oversized RRSIG records, which when processed by the vulnerable BIND versions trigger the memory access violations.
Mitigation strategies for CVE-2011-1910 primarily involve applying the appropriate software patches released by ISC for each affected version branch. Organizations should upgrade to BIND versions 9.7.3-P1, 9.8.0-P2, 9.4-ESV-R4-P1, or 9.6-ESV-R4-P1 respectively, depending on their current deployment. Additional protective measures include implementing DNS response validation mechanisms, configuring rate limiting for DNS responses, and deploying network monitoring to detect unusual DNS traffic patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-129, which addresses improper validation of array index values, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing DNS security extensions and configuring proper access controls to limit exposure to potentially malicious DNS responses from untrusted sources.