CVE-2009-2547 in Arma 2
Summary
by MITRE
Integer underflow in Armed Assault (aka ArmA) 1.14 and earlier, and 1.16 beta, and Armed Assault II 1.02 and earlier allows remote attackers to cause a denial of service (crash) via a VoIP over Network (VON) packet to port 2305 with a negative packet_size value, which triggers a buffer over-read.
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Analysis
by VulDB Data Team • 12/16/2017
The vulnerability described in CVE-2009-2547 represents a critical integer underflow flaw affecting the gaming engines of Armed Assault and Armed Assault II versions up to their respective vulnerable releases. This issue specifically targets the VoIP over Network protocol implementation used for voice communication within the game's multiplayer environment. The vulnerability manifests when the game engine processes network packets destined for port 2305, which serves as the default communication port for the VON system. When an attacker sends a malformed packet containing a negative packet_size value, the integer underflow condition occurs during the processing of these network communications, leading to unpredictable behavior in the application's memory management routines.
The technical exploitation of this vulnerability involves crafting a malicious network packet that deliberately sets the packet_size field to a negative integer value. This negative value, when processed through the game's network handling code, causes an integer underflow that results in the calculation of an invalid buffer size. The subsequent buffer over-read operation attempts to access memory locations beyond the allocated buffer boundaries, causing the application to crash and terminate unexpectedly. This behavior represents a classic denial of service condition that can be triggered remotely without requiring any authentication or special privileges from the attacker.
From an operational perspective, this vulnerability presents a significant risk to multiplayer gaming environments where Armed Assault and Armed Assault II are deployed. The remote exploitation capability means that any player connected to a vulnerable game server can potentially cause service disruption for other players, effectively creating a vector for malicious actors to degrade the gaming experience. The vulnerability affects not just individual players but entire gaming communities, as a single malicious packet can cause multiple players to disconnect or crash their game clients. The impact extends beyond simple disruption to include potential data loss or corruption in game sessions, as the application crashes occur during active gameplay scenarios.
The underlying weakness stems from inadequate input validation within the network packet processing code, specifically failing to properly validate the packet_size field before using it in buffer calculations. This vulnerability aligns with CWE-191, which identifies integer underflow conditions as a common source of memory corruption vulnerabilities in software systems. The flaw demonstrates poor defensive programming practices where the developers did not implement proper boundary checks or range validation for critical numerical parameters. From an attack framework perspective, this vulnerability could be categorized under ATT&CK technique T1499, which covers network denial of service attacks, and T1595, which involves reconnaissance activities targeting network protocols and services.
Mitigation strategies for this vulnerability require immediate patching of the affected game versions to address the integer underflow condition in the network packet processing routines. Game server administrators should implement network filtering rules to prevent malformed packets from reaching vulnerable game servers, though this approach may not be completely effective against all attack vectors. The most effective solution involves updating to patched versions of the game software where the integer underflow has been corrected through proper input validation and boundary checking mechanisms. Additionally, implementing network monitoring solutions to detect and alert on unusual packet patterns can help identify potential exploitation attempts. Organizations running game servers should also consider implementing rate limiting and packet validation measures to reduce the effectiveness of potential denial of service attacks targeting this specific vulnerability.