CVE-2006-1194 in ENet library
Summary
by MITRE
Integer signedness error in the enet_protocol_handle_incoming_commands 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 with a large command length value, which leads to an invalid memory access.
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Analysis
by VulDB Data Team • 03/16/2025
The vulnerability identified as CVE-2006-1194 represents a critical integer signedness error within the ENet library's network protocol handling mechanism. This flaw exists in the enet_protocol_handle_incoming_commands function located in protocol.c of the ENet library version from July 2005 and earlier. The issue manifests when processing network packets containing command length values that exceed normal operational parameters, creating a scenario where the application becomes vulnerable to remote exploitation. The vulnerability affects multiple high-profile applications including Cube, Sauerbraten, and Duke3d_w32, demonstrating the widespread impact of this fundamental coding error.
The technical root cause of this vulnerability stems from an improper handling of integer values during packet processing operations. When the enet_protocol_handle_incoming_commands function receives a packet with an unusually large command length value, the signed integer comparison fails to properly validate the incoming data. This signedness error occurs because the system treats unsigned command length values as signed integers during processing, leading to unexpected behavior when large positive values are interpreted as negative numbers. The flaw creates a condition where the program attempts to allocate or access memory using calculated values that fall outside the valid memory boundaries, resulting in invalid memory access patterns.
The operational impact of this vulnerability is severe and directly translates to a denial of service condition that can crash affected applications. Remote attackers can exploit this weakness by crafting malicious network packets with oversized command length fields, causing the target application to crash and become unavailable to legitimate users. The vulnerability does not appear to enable arbitrary code execution or privilege escalation, but the denial of service aspect makes it particularly dangerous in networked gaming environments and multiplayer applications where continuous availability is critical. The crash occurs during normal network communication processing, making it difficult to distinguish between legitimate network traffic and malicious attacks.
This vulnerability aligns with CWE-191, Integer Underflow (Wrap or Wraparound), and more specifically with CWE-190, Integer Overflow or Wraparound, as the signed integer handling error results in unexpected wrapping behavior that leads to invalid memory access. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, Network Denial of Service, and potentially T1595.001, Network Scanning, as attackers may need to probe for vulnerable systems before launching the actual denial of service attack. The exploitation requires minimal privileges and can be executed remotely, making it particularly attractive to threat actors seeking to disrupt network services. Organizations using affected versions of ENet should implement immediate mitigation strategies including patching to newer library versions, implementing network segmentation, and deploying intrusion detection systems to monitor for suspicious packet patterns.
The remediation approach for this vulnerability centers on updating to patched versions of the ENet library where the integer signedness error has been corrected through proper validation of command length values. Developers should ensure that all incoming packet data undergoes thorough validation before being processed, particularly focusing on integer bounds checking and unsigned value handling. Network administrators should monitor for exploitation attempts through network traffic analysis and implement rate limiting measures to prevent rapid exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and integer handling in network protocol implementations, as even seemingly minor coding errors can result in significant availability impacts across multiple applications and platforms.