CVE-2006-1195 in ENet library
Summary
by MITRE
The enet_protocol_handle_send_fragment function in protocol.c for ENet library CVS version Jul 2005 and earlier, as used in products including (1) Cube, (2) Sauerbraten, and (3) Duke3d_w32, allows remote attackers to cause a denial of service (application crash) via a packet fragment with a large total data size, which triggers an application abort when memory allocation fails.
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Analysis
by VulDB Data Team • 09/07/2017
The vulnerability described in CVE-2006-1195 represents a critical memory management flaw within the ENet library implementation that affects multiple gaming applications and network protocols. This issue manifests in the enet_protocol_handle_send_fragment function which processes fragmented network packets, specifically when handling packets with excessive total data sizes that exceed normal operational parameters. The vulnerability exists in the CVS version of ENet from July 2005 and earlier, making it a legacy issue that impacted numerous applications including popular games like Cube, Sauerbraten, and Duke3d_w32. The flaw demonstrates a fundamental weakness in input validation and memory allocation handling that directly compromises system stability.
The technical exploitation of this vulnerability occurs when a remote attacker sends a specially crafted packet fragment containing an abnormally large total data size. When the enet_protocol_handle_send_fragment function attempts to process this malformed packet, it triggers a memory allocation failure due to the excessive data requirements. This allocation failure causes the application to abort and crash, resulting in a denial of service condition that affects legitimate users of the affected applications. The vulnerability specifically targets the memory allocation routines within the network protocol handling code, where insufficient bounds checking allows malicious data to bypass normal validation mechanisms. This type of flaw falls under CWE-122, which describes improper restriction of operations within the bounds of a memory buffer, and more specifically aligns with CWE-704, concerning incorrect type conversion or cast.
The operational impact of this vulnerability extends beyond simple application crashes to potentially disrupt entire gaming sessions and network communications. In multiplayer gaming environments where these applications are commonly used, an attacker could systematically crash game servers or client applications, making the gaming experience unreliable and potentially unusable. The vulnerability is particularly concerning because it can be exploited remotely without requiring authentication or special privileges, making it accessible to anyone who can send network packets to the target system. This characteristic places the vulnerability within ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how seemingly minor implementation flaws can create significant operational disruptions in real-world scenarios.
Mitigation strategies for this vulnerability require immediate patching of the affected ENet library versions, with the most effective solution being the upgrade to a patched version that properly validates packet fragment sizes and implements robust memory allocation error handling. System administrators should also implement network monitoring to detect unusual packet fragmentation patterns that may indicate exploitation attempts. Additionally, applications using the ENet library should incorporate defensive programming practices including proper input validation, memory allocation error checking, and graceful degradation mechanisms when resource constraints occur. The vulnerability highlights the importance of thorough testing of network protocol implementations and proper handling of edge cases in memory management operations, particularly in environments where network applications must handle untrusted input from remote sources. Organizations should also consider implementing network segmentation and access controls to limit exposure to potential exploitation while patches are being deployed.