CVE-2016-1286 in BIND
Summary
by MITRE
named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a crafted signature record for a DNAME record, related to db.c and resolver.c.
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Analysis
by VulDB Data Team • 07/10/2022
The vulnerability identified as CVE-2016-1286 represents a critical denial of service flaw within the Internet Systems Consortium BIND software version 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4. This vulnerability specifically targets the handling of crafted signature records associated with DNAME records, creating a condition where the named daemon can be forcibly terminated through assertion failures. The flaw exists in the core database and resolver components of BIND, making it particularly dangerous as it can be exploited remotely without requiring authentication or special privileges. The vulnerability demonstrates the inherent risks in DNS server implementations where malformed data processing can lead to complete service disruption.
The technical root cause of this vulnerability lies in the improper validation of signature records within DNAME record processing within the BIND software's database and resolver modules. When a malicious actor crafts a specially formatted signature record that references a DNAME record, the software's assertion mechanisms fail to properly handle the malformed input, resulting in an assertion failure that terminates the named daemon process. This issue stems from inadequate input sanitization and error handling within the db.c and resolver.c source files, where the software does not properly validate the structure and content of signature records before attempting to process them. The vulnerability operates at the protocol level where DNS servers must handle various record types including signature records, making it a fundamental flaw in DNS server security architecture.
The operational impact of CVE-2016-1286 is severe as it enables remote attackers to perform denial of service attacks against DNS infrastructure without requiring any authentication credentials. This vulnerability affects organizations that rely on BIND as their primary DNS server implementation, potentially causing widespread service disruption across networks dependent on DNS resolution. The attack vector is particularly concerning because it can be executed from any remote location with network access to the vulnerable DNS server, making it an attractive target for attackers seeking to disrupt network services. The assertion failure that occurs during processing results in the daemon exiting unexpectedly, which can lead to cascading failures in DNS resolution across dependent systems and services.
Organizations affected by this vulnerability should immediately implement mitigations including upgrading to BIND versions 9.9.8-P4 or 9.10.3-P4, which contain the necessary patches to address the assertion failure issue. Additionally, network administrators should consider implementing firewall rules to restrict access to DNS servers from untrusted networks, though this approach provides only partial protection since the vulnerability can be exploited through legitimate DNS query processing. The mitigation strategy should also include monitoring for unusual DNS traffic patterns that might indicate exploitation attempts, and implementing intrusion detection systems that can identify malicious signature record patterns. This vulnerability aligns with CWE-691, which addresses inadequate input validation leading to assertion failures, and represents a significant concern within the ATT&CK framework under the denial of service tactic where adversaries seek to disrupt services by exploiting software flaws.
The broader implications of this vulnerability extend beyond immediate service disruption to highlight the critical importance of proper input validation in DNS server implementations. DNS servers operate as fundamental infrastructure components, and vulnerabilities that cause daemon termination can have cascading effects throughout enterprise networks and internet infrastructure. This flaw demonstrates the need for comprehensive security testing of DNS server implementations, particularly focusing on edge cases involving malformed records and signature processing. Organizations should also consider implementing redundant DNS infrastructure and proper failover mechanisms to minimize the impact of such vulnerabilities, as the disruption caused by this vulnerability can affect thousands of clients depending on the scale of the affected DNS server deployment.