CVE-2005-2316 in DNRD
Summary
by MITRE
Domain Name Relay Daemon (DNRD) before 2.19.1 allows remote attackers to cause a denial of service (infinite recursion) via a DNS packet that uses message compression in the QNAME and two pointers that point to each other (circular buffer).
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/04/2019
The Domain Name Relay Daemon (DNRD) vulnerability identified as CVE-2005-2316 represents a critical denial of service flaw that affects versions prior to 2.19.1. This vulnerability exploits the daemon's handling of DNS packets containing specific message compression patterns, creating a condition where the system enters infinite recursion during packet processing. The flaw specifically manifests when a malicious DNS packet contains a QNAME field with message compression that includes two pointers referencing each other, forming a circular buffer structure that the daemon cannot properly resolve.
The technical implementation of this vulnerability stems from inadequate input validation and recursive pointer resolution mechanisms within the DNRD's DNS packet parsing logic. When the daemon encounters a DNS packet with circular pointers in the QNAME section, it attempts to resolve these pointers recursively without proper bounds checking or cycle detection. This creates an infinite loop where the parser continuously follows the circular references, consuming system resources and ultimately causing the daemon to become unresponsive. The vulnerability operates at the application layer and specifically targets the DNS protocol implementation within the relay daemon, making it particularly dangerous for systems that rely on DNS services for network operations.
From an operational impact perspective, this vulnerability enables remote attackers to execute effective denial of service attacks against systems running vulnerable versions of DNRD. The infinite recursion consumes CPU cycles and memory resources, potentially leading to system crashes or complete service unavailability. Network administrators face significant challenges in mitigating this vulnerability since the attack can be launched remotely without requiring authentication or special privileges. The impact extends beyond individual system compromise to potentially affect entire network infrastructures that depend on DNS services, particularly in environments where DNS relay functionality is critical for network operations.
The vulnerability maps to CWE-121 in the Common Weakness Enumeration, specifically addressing issues related to buffer overflow conditions and improper handling of recursive data structures. From an MITRE ATT&CK framework perspective, this represents a denial of service technique that can be categorized under T1499.004 for network denial of service, potentially supporting broader attack chains that could lead to further system compromise. Organizations should implement immediate patching strategies to upgrade to DNRD version 2.19.1 or later, which contains proper pointer validation and cycle detection mechanisms. Additional mitigations include implementing network segmentation to isolate DNS services, deploying intrusion detection systems to monitor for suspicious DNS traffic patterns, and establishing robust monitoring procedures to detect unusual resource consumption patterns that may indicate exploitation attempts.