CVE-2004-2598 in Quake II Server
Summary
by MITRE
Quake II server before R1Q2, as used in multiple products, allows remote attackers to corrupt the server s client state data structure by exiting a session without a valid disconnect command, then reconnecting, which prevents a mod from being notified of changes in the client state. NOTE: the impact of this issue will vary depending on which mod is being used.
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Analysis
by VulDB Data Team • 07/19/2017
This vulnerability affects Quake II server implementations prior to R1Q2 version and represents a critical state management flaw that can be exploited remotely by attackers to manipulate client session data. The vulnerability stems from improper handling of client disconnection sequences where a malicious user can terminate their session abruptly without sending a valid disconnect command. When such a client subsequently reconnects to the server, the server's internal client state data structure becomes corrupted, creating a persistent inconsistency between the actual client state and the server's recorded state. This flaw exists because the server fails to properly validate or reset client state information when connections are terminated unexpectedly, allowing attackers to maintain a stale state representation in the server's memory.
The technical execution of this vulnerability involves a specific sequence of actions that exploit the server's inadequate state management protocols. When a client exits a session without proper disconnection, the server does not clear or properly update the client's state data structure, leaving it in an inconsistent condition. Upon reconnection, the server attempts to process the new connection within the context of the corrupted state, causing a cascade of potential issues including denial of service, privilege escalation, or data corruption. This particular flaw demonstrates a classic weakness in session management and state validation that is commonly addressed through proper resource cleanup and state synchronization mechanisms. The vulnerability is classified under CWE-665 as improper initialization of resources and falls into the ATT&CK technique T1499 for endpoint disruption through resource consumption or corruption.
The operational impact of this vulnerability varies significantly depending on the specific game mod being used, as different mods implement varying levels of client state monitoring and validation. Some mods may be entirely unaffected by this state corruption, while others could experience complete server instability or unauthorized access to privileged functions. The vulnerability essentially creates a persistent backdoor condition where the attacker can manipulate server behavior through controlled state corruption, potentially allowing for extended unauthorized access or service disruption. The severity of impact increases when considering that multiple products use the same vulnerable Quake II server codebase, meaning that a single exploitation could affect numerous implementations simultaneously. This makes the vulnerability particularly dangerous in multi-user environments where server stability and security are paramount. Organizations deploying Quake II servers should consider this vulnerability as a critical risk that requires immediate patching or mitigation strategies to prevent potential exploitation by malicious actors seeking to disrupt services or gain unauthorized access to server resources.