CVE-2016-1285 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 malformed packet to the rndc (aka control channel) interface, related to alist.c and sexpr.c.
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Analysis
by VulDB Data Team • 07/10/2022
The vulnerability identified as CVE-2016-1285 represents a critical denial of service weakness in the Internet Systems Consortium BIND DNS server software. This flaw affects versions 9.x prior to 9.9.8-P4 and 9.10.x prior to 9.10.3-P4, specifically targeting the remote command (rndc) interface that serves as the control channel for BIND daemon management. The vulnerability stems from insufficient input validation within the alist.c and sexpr.c source code modules, which handle list and sexpression processing respectively. Attackers can exploit this weakness by sending carefully crafted malformed packets to the rndc interface, triggering an assertion failure that ultimately causes the BIND daemon to terminate unexpectedly. This behavior constitutes a classic denial of service attack vector that can be executed remotely without requiring authentication or special privileges, making it particularly dangerous in production environments where DNS services are critical infrastructure components.
The technical implementation of this vulnerability demonstrates a fundamental flaw in the software's error handling mechanisms within the recursive parsing routines. When the rndc interface receives a malformed packet containing invalid list structures or malformed sexpressions, the parsing code fails to properly validate the input before attempting to process it. The assertion failure occurs during the evaluation of list elements or sexpression components, causing the daemon to crash and exit immediately. This type of vulnerability falls under CWE-248, which describes an unchecked exception or assertion failure that leads to program termination, and represents a direct violation of the principle of robust error handling in network services. The attack surface is particularly concerning because the rndc interface typically listens on a well-known port and may be accessible from untrusted networks, especially when default configurations are used without proper firewall restrictions.
The operational impact of CVE-2016-1285 extends beyond simple service disruption to potentially compromise entire network infrastructure availability. When a BIND daemon crashes due to this vulnerability, all DNS resolution services provided by that server become unavailable until the daemon is manually restarted or the system automatically recovers. This affects not only the immediate DNS server but can cascade through dependent systems that rely on proper DNS resolution for network connectivity, email services, web browsing, and other critical network operations. Organizations using affected BIND versions face significant risk of service degradation during attacks, particularly in environments where DNS servers are not properly segmented or where automated monitoring systems fail to detect the daemon failures promptly. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a common pattern of resource exhaustion or assertion failures that can be exploited to maintain persistent service disruption.
Mitigation strategies for CVE-2016-1285 require immediate implementation of software updates to the affected BIND versions, with the most effective solution being the upgrade to patched releases that include proper input validation and error handling mechanisms. Organizations should prioritize updating to BIND 9.9.8-P4 or 9.10.3-P4, which contain the necessary fixes to prevent malformed packet processing from causing daemon crashes. Additionally, network administrators should implement proper firewall rules to restrict access to the rndc interface, limiting it to trusted management networks only and ensuring that the control channel is not exposed to untrusted external hosts. Network segmentation practices should be enforced to isolate DNS servers from general network traffic, and monitoring systems should be enhanced to detect daemon failures and automatically trigger alerting mechanisms. The vulnerability also highlights the importance of regular security assessments and penetration testing to identify similar weaknesses in other network services that may be vulnerable to similar assertion failure exploitation techniques. Organizations should also consider implementing intrusion detection systems that can monitor for unusual packet patterns that might indicate exploitation attempts against the rndc interface.