CVE-2013-2266 in BIND
Summary
by MITRE
libdns in ISC BIND 9.7.x and 9.8.x before 9.8.4-P2, 9.8.5 before 9.8.5b2, 9.9.x before 9.9.2-P2, and 9.9.3 before 9.9.3b2 on UNIX platforms allows remote attackers to cause a denial of service (memory consumption) via a crafted regular expression, as demonstrated by a memory-exhaustion attack against a machine running a named process.
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Analysis
by VulDB Data Team • 05/06/2021
The vulnerability identified as CVE-2013-2266 represents a critical memory exhaustion flaw within the libdns library component of Internet Systems Consortium BIND DNS server software. This issue affects multiple versions of BIND 9.7.x, 9.8.x, and 9.9.x series, specifically before the mentioned patch releases, creating a persistent security gap that could be exploited by remote attackers to consume excessive system memory resources. The vulnerability manifests when the DNS server processes malformed regular expressions during DNS query handling, leading to uncontrolled memory growth that can ultimately result in system instability and denial of service conditions.
The technical root cause of this vulnerability stems from insufficient input validation and sanitization within the regular expression processing functionality of the libdns library. When a maliciously crafted regular expression is submitted through DNS queries, the parsing mechanism fails to properly handle the complexity and resource requirements of such expressions, causing the named process to allocate increasingly large amounts of memory without proper bounds checking. This behavior aligns with CWE-122, which describes improper restriction of operations within the bounds of a memory buffer, and more specifically relates to CWE-400, which covers unchecked resource allocation vulnerabilities. The flaw exists at the intersection of regular expression engine implementation and memory management within the DNS resolution process, creating an attack surface where computational resources can be consumed exponentially.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can severely compromise the availability and stability of DNS infrastructure across affected systems. Remote attackers can exploit this weakness by crafting specific DNS queries containing malformed regular expressions that trigger memory allocation patterns leading to system resource exhaustion. The attack can be executed without authentication and requires minimal technical expertise, making it particularly dangerous for widespread deployment. This vulnerability directly maps to ATT&CK technique T1499.004, which describes network denial of service attacks targeting DNS services, and represents a significant threat to DNS server availability. The memory consumption pattern typically results in the named process consuming all available system memory, causing system crashes, service interruptions, and potentially affecting other network services running on the same infrastructure.
Mitigation strategies for CVE-2013-2266 primarily focus on immediate patch deployment and system hardening measures. Organizations should prioritize upgrading to patched versions of BIND software, specifically versions 9.8.4-P2, 9.8.5b2, 9.9.2-P2, and 9.9.3b2 respectively, which contain the necessary fixes to prevent the memory exhaustion behavior. Network administrators should implement rate limiting and query filtering mechanisms to reduce the impact of potential attacks while patches are being deployed. Additionally, monitoring systems should be configured to detect unusual memory consumption patterns in DNS processes, enabling early detection of exploitation attempts. The vulnerability demonstrates the importance of proper input validation in security-critical systems and highlights the need for robust resource management practices in network infrastructure components. Organizations should also consider implementing intrusion detection systems that can identify and block suspicious DNS query patterns that may indicate exploitation attempts, providing an additional layer of defense against this type of resource exhaustion attack.