CVE-2014-0591 in BIND
Summary
by MITRE
The query_findclosestnsec3 function in query.c in named in ISC BIND 9.6, 9.7, and 9.8 before 9.8.6-P2 and 9.9 before 9.9.4-P2, and 9.6-ESV before 9.6-ESV-R10-P2, allows remote attackers to cause a denial of service (INSIST assertion failure and daemon exit) via a crafted DNS query to an authoritative nameserver that uses the NSEC3 signing feature.
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Analysis
by VulDB Data Team • 06/04/2021
The vulnerability identified as CVE-2014-0591 represents a critical denial of service flaw within the Internet Systems Consortium BIND DNS server implementation. This vulnerability specifically affects versions 9.6, 9.7, and 9.8 before their respective patch releases, as well as 9.9 before 9.9.4-P2 and the 9.6-ESV branch before 9.6-ESV-R10-P2. The issue stems from a flaw in the query_findclosestnsec3 function located within the query.c source file, which is responsible for handling DNS queries in authoritative name server configurations that utilize the NSEC3 signing feature.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a specially malformed DNS query that triggers an assertion failure within the named daemon process. This assertion failure specifically manifests as an INSIST assertion, which is a critical error handling mechanism designed to detect programming errors or unexpected conditions in the software. When this assertion fails, it causes the named daemon to terminate abruptly, resulting in a complete denial of service for all DNS resolution requests handled by that authoritative server. The vulnerability is particularly concerning because it affects the core DNS resolution functionality and can be triggered through simple network-based attacks without requiring authentication or specialized privileges.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise the availability of DNS infrastructure that relies on ISC BIND servers with NSEC3 signing enabled. When an authoritative nameserver becomes unavailable due to this assertion failure, it can cascade into broader network issues affecting applications and services that depend on DNS resolution for connectivity. The vulnerability affects the fundamental DNS security model since NSEC3 is designed to provide authenticated denial of existence for DNS names, making this flaw particularly dangerous for servers that implement DNS security extensions. Organizations running affected versions of BIND with NSEC3 enabled are at significant risk of experiencing service outages that can last until the daemon is manually restarted or the system is rebooted.
The vulnerability aligns with CWE-122, which describes buffer overflow conditions in memory management, and represents a specific instance of improper input validation where the query handling mechanism fails to properly validate the structure of incoming DNS queries. From an attacker's perspective, this vulnerability maps to ATT&CK technique T1499.004, which involves network disruption through denial of service attacks. The flaw demonstrates how seemingly benign DNS query processing can become a vector for service disruption, particularly when the software fails to handle malformed input gracefully. Organizations should prioritize immediate patching of affected systems and implement network monitoring to detect potential exploitation attempts, as the vulnerability can be easily automated and does not require significant technical expertise to execute successfully. The affected configurations typically include authoritative DNS servers that have enabled NSEC3 signing as part of their DNS security implementation, making this issue particularly relevant for organizations implementing DNS security extensions to protect against various DNS-related attacks.