CVE-2003-0212 in rinetd
Summary
by MITRE
handleAccept in rinetd before 0.62 does not properly resize the connection list when it becomes full and sets an array index incorrectly, which allows remote attackers to cause a denial of service and possibly execute arbitrary code via a large number of connections.
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Analysis
by VulDB Data Team • 04/29/2019
The vulnerability described in CVE-2003-0212 affects rinetd version 0.61 and earlier, representing a critical flaw in the network proxy daemon's connection handling mechanism. This issue resides within the handleAccept function which manages incoming connection requests and maintains an internal connection list array. The vulnerability stems from improper memory management during connection list resizing operations when the maximum capacity is reached, creating a scenario where the application fails to correctly manage its internal data structures during high-concurrency connection attempts.
The technical flaw manifests when rinetd processes multiple simultaneous connection requests that exceed the predefined connection limit. The handleAccept function fails to properly resize the connection list array and instead sets an incorrect array index value during the resize operation. This improper index handling creates a buffer overflow condition or memory corruption scenario that can be exploited by remote attackers. The vulnerability operates at the protocol level where attackers can flood the service with connection attempts, triggering the flawed resize logic and causing unpredictable behavior in the application's memory management.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution. When the connection list reaches its maximum capacity and the resize operation fails, the application may experience memory corruption that could allow attackers to execute arbitrary code with the privileges of the rinetd process. This represents a significant security risk as the service typically runs with elevated privileges to manage network connections. The vulnerability is particularly dangerous in environments where rinetd serves as a network proxy or port forwarding service, as it could allow attackers to compromise entire network segments.
From a cybersecurity perspective, this vulnerability maps to CWE-121 for buffer overflow conditions and CWE-787 for out-of-bounds write operations. The attack pattern aligns with the ATT&CK technique T1499.004 for network denial of service and potentially T1059 for remote code execution through service manipulation. The vulnerability demonstrates poor input validation and memory management practices that are common in legacy network services. Organizations should implement immediate mitigations including upgrading to rinetd version 0.62 or later, implementing connection rate limiting, and monitoring for unusual connection patterns that might indicate exploitation attempts.
The root cause of this vulnerability highlights the importance of proper array boundary checking and memory management in network services handling concurrent connections. Modern secure coding practices would require bounds checking before array index operations and proper error handling during memory allocation. The vulnerability also underscores the risks associated with maintaining legacy network services and the necessity of regular security updates to address known memory corruption issues. Network administrators should consider implementing additional security controls such as firewall rules limiting connection attempts and intrusion detection systems monitoring for potential exploitation attempts.