CVE-2015-5477 in BIND
Summary
by MITRE
named in ISC BIND 9.x before 9.9.7-P2 and 9.10.x before 9.10.2-P3 allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit) via TKEY queries.
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Analysis
by VulDB Data Team • 12/20/2024
The vulnerability identified as CVE-2015-5477 represents a critical denial of service weakness within the Internet Systems Consortium BIND DNS server software. This flaw affects versions 9.x before 9.9.7-P2 and 9.10.x before 9.10.2-P3, making it a widespread issue across multiple generations of the BIND software. The vulnerability specifically targets the handling of TKEY queries, which are used for secure DNS transactions and key exchange mechanisms within DNS security extensions. The issue manifests when the named daemon processes malformed or specially crafted TKEY queries, leading to an assertion failure that causes the daemon to terminate unexpectedly.
The technical implementation of this vulnerability stems from inadequate input validation within the TKEY query processing module of BIND. When a remote attacker sends a malicious TKEY query to a vulnerable BIND server, the software fails to properly validate the query structure and content before attempting to process it. This validation gap results in an assertion failure within the software's internal logic, triggering a cascade that forces the named daemon to exit abruptly. The assertion failure occurs during the processing phase where the software expects certain conditions to be met but encounters invalid data that violates these assumptions. This particular weakness falls under the CWE-691 category of Insufficient Control Flow Management, specifically related to improper handling of assertion failures that can lead to program termination.
The operational impact of CVE-2015-5477 is severe for organizations relying on affected BIND versions, as it can be exploited to cause complete service disruption. Remote attackers can leverage this vulnerability to perform denial of service attacks against DNS infrastructure without requiring authentication or special privileges. The daemon exit creates a complete service outage that requires manual intervention to restore, as the named process must be restarted to re-establish DNS service availability. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under the T1499 category of Network Denial of Service, specifically targeting DNS services and infrastructure. Organizations using affected versions may experience extended downtime during which DNS resolution fails completely, potentially affecting thousands of dependent services and applications.
Mitigation strategies for CVE-2015-5477 primarily involve upgrading to patched versions of BIND software, specifically versions 9.9.7-P2 or 9.10.2-P3 and later. Organizations should prioritize immediate patch deployment across all affected DNS servers within their infrastructure to eliminate the vulnerability. Additionally, network-level mitigations can be implemented through firewall rules that restrict TKEY query processing or by configuring access controls that limit which hosts can send TKEY queries to authoritative DNS servers. The vulnerability highlights the importance of input validation and robust error handling in critical network infrastructure software, as outlined in security best practices from organizations such as the SANS Institute and NIST. System administrators should also implement monitoring solutions to detect unusual patterns of TKEY query traffic that might indicate exploitation attempts, providing early warning capabilities for potential attacks.