CVE-2008-6705 in S.T.A.L.K.E.R.: Shadow of Chernobyl
Summary
by MITRE
The MultipacketReciever::RecievePacket function in S.T.A.L.K.E.R.: Shadow of Chernobyl 1.0006 and earlier allows remote attackers to cause a denial of service (server termination) via a crafted packet without an expected 0xe0 or 0xe1 value, which triggers the INT3 instruction.
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Analysis
by VulDB Data Team • 12/14/2017
The vulnerability identified as CVE-2008-6705 resides within the MultipacketReciever::ReceivePacket function of S.T.A.L.K.E.R.: Shadow of Chernobyl version 1.0006 and earlier. This represents a critical security flaw that affects the game's network communication protocol implementation, specifically targeting the server-side packet processing mechanism. The vulnerability manifests when the game server receives a specially crafted network packet that lacks the expected 0xe0 or 0xe1 value bytes that the function typically anticipates during normal operation.
The technical exploitation of this vulnerability occurs through a deliberate manipulation of network packet structure that bypasses normal validation procedures within the game's networking code. When the MultipacketReciever::ReceivePacket function processes a packet that does not contain the expected 0xe0 or 0xe1 values, the code path triggers an INT3 instruction, which is a software interrupt typically used for debugging purposes. This instruction causes the executing process to immediately terminate and crash, resulting in a complete server shutdown that affects all connected players and prevents further gameplay.
From an operational perspective, this vulnerability presents a significant risk to game servers that host multiplayer sessions for S.T.A.L.K.E.R.: Shadow of Chernobyl. Attackers can easily exploit this weakness by crafting malicious network packets and transmitting them to the target server, requiring minimal technical expertise or resources to execute the attack successfully. The denial of service condition effectively renders the game server unavailable to legitimate players, potentially disrupting gaming sessions, competitive tournaments, or community events that rely on stable server infrastructure. This vulnerability aligns with CWE-122, which describes improper restriction of operations within a limited error handling context, and demonstrates how inadequate input validation can lead to catastrophic system failures.
The impact of this vulnerability extends beyond simple server downtime as it affects the overall gaming experience and community engagement within the S.T.A.L.K.E.R.: Shadow of Chernobyl ecosystem. Server administrators and game operators face the challenge of maintaining service availability while dealing with potential exploitation attempts that could be used to disrupt gameplay or create competitive advantages through service disruption. The vulnerability also highlights the importance of proper error handling and input validation in networked applications, particularly those that process untrusted data from remote sources. According to ATT&CK framework, this represents a privilege escalation and denial of service technique that can be categorized under T1499, which covers network denial of service attacks.
Mitigation strategies for this vulnerability involve implementing proper input validation within the MultipacketReciever::ReceivePacket function to ensure that all received packets contain expected values before processing continues. Server administrators should update to version 1.0007 or later where this vulnerability has been patched, as the developers recognized and addressed the issue through code modifications that properly handle packets without the expected 0xe0 or 0xe1 values. Additionally, network-level protections such as packet filtering rules and intrusion detection systems can help identify and block malicious traffic patterns associated with this exploit. The vulnerability serves as a reminder of the critical importance of robust error handling in networked applications and demonstrates how seemingly minor input validation gaps can lead to complete system compromise through denial of service attacks.