CVE-2006-2393 in Empire Server
Summary
by MITRE
The client_cmd function in Empire 4.3.2 and earlier allows remote attackers to cause a denial of service (application crash) by causing long text strings to be appended to the player->client buffer, which causes an invalid memory access.
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Analysis
by VulDB Data Team • 09/06/2017
The vulnerability identified as CVE-2006-2393 resides within the Empire game server software version 4.3.2 and earlier, representing a critical denial of service flaw that can be exploited remotely by attackers to crash the application. This vulnerability specifically targets the client_cmd function which handles command processing from connected clients. The flaw manifests when maliciously crafted long text strings are appended to the player->client buffer, creating a condition where the application attempts to access invalid memory locations. The issue stems from inadequate input validation and buffer management within the client command processing pipeline, making it susceptible to exploitation through carefully constructed malicious payloads.
From a technical perspective, this vulnerability operates as a buffer overflow condition that occurs during the processing of client commands in the Empire server implementation. The client_cmd function fails to properly validate the length of incoming text data before appending it to the player->client buffer, which has predetermined memory boundaries. When the accumulated text exceeds these boundaries, the application encounters invalid memory access patterns that result in segmentation faults or similar memory corruption errors. This type of vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, though the specific implementation details suggest a more complex memory management issue. The vulnerability is particularly dangerous because it can be triggered remotely without requiring authentication or special privileges, making it an attractive target for malicious actors seeking to disrupt server operations.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged to create persistent availability issues for legitimate users. Attackers can repeatedly send malformed command strings to cause the server to crash and restart, leading to extended periods of unavailability that can severely impact gameplay and user experience. The server's stability is compromised as repeated exploitation attempts can cause cascading failures in the application's memory management systems. In a multiplayer gaming environment, this vulnerability can be weaponized to create denial of service attacks that affect all connected players, potentially leading to significant revenue loss for game operators and damage to service reputation. The vulnerability also represents a potential vector for more sophisticated attacks if the memory corruption can be manipulated to execute arbitrary code, though the current analysis indicates it primarily functions as a crash mechanism.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and buffer size management within the client command processing function. The most effective immediate solution involves adding length checks to ensure that text strings appended to the player->client buffer do not exceed predetermined safe limits. System administrators should implement rate limiting and connection monitoring to detect and block suspicious traffic patterns that may indicate exploitation attempts. Regular updates and patches should be applied to move beyond the vulnerable Empire 4.3.2 version, as this vulnerability was likely addressed in subsequent releases through improved memory management practices. Network-level protections such as intrusion detection systems can be configured to monitor for unusual command processing patterns, while application-level safeguards including memory protection mechanisms and stack canaries should be implemented to prevent exploitation. The vulnerability also highlights the importance of adhering to secure coding practices and conducting regular security audits to identify similar buffer management issues in legacy applications, aligning with the ATT&CK framework's defensive strategies for preventing memory corruption exploits through proper input validation and secure coding standards.