CVE-2019-20893 in Call of Duty Modern Warfare 2
Summary
by MITRE
An issue was discovered in Activision Infinity Ward Call of Duty Modern Warfare 2 through 2019-12-11. PartyHost_HandleJoinPartyRequest has a buffer overflow vulnerability and can be exploited by using a crafted joinParty packet. This can be utilized to conduct arbitrary code execution on a victim's machine.
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Analysis
by VulDB Data Team • 07/01/2020
The vulnerability identified as CVE-2019-20893 represents a critical buffer overflow flaw within Activision Infinity Ward's Call of Duty Modern Warfare 2 game client, specifically affecting versions released through December 11, 2019. This security weakness resides in the PartyHost_HandleJoinPartyRequest function which processes incoming network packets from other players attempting to join a multiplayer session. The flaw stems from inadequate input validation and bounds checking when handling the joinParty packet data structure, creating an exploitable condition that allows remote attackers to manipulate memory layout and execute malicious code on targeted systems. The vulnerability demonstrates characteristics consistent with CWE-121, heap-based buffer overflow, where insufficient boundary checks enable attackers to overwrite adjacent memory locations and potentially hijack program execution flow.
The technical exploitation of this vulnerability requires an attacker to craft a specially formatted joinParty packet that exceeds the allocated buffer size within the PartyHost_HandleJoinPartyRequest function. When the game client processes this malformed packet, the excessive data overflows into adjacent memory regions, potentially corrupting critical program variables, return addresses, or function pointers. This overflow condition creates opportunities for attackers to inject and execute arbitrary code with the privileges of the targeted user, effectively allowing remote code execution without requiring local system access or authentication. The attack vector operates entirely through network communication, making it particularly dangerous as it can be exploited against any player participating in online multiplayer sessions.
The operational impact of CVE-2019-20893 extends beyond simple remote code execution to encompass significant security implications for online gaming environments and player data integrity. Game servers and client systems become vulnerable to unauthorized access, potentially enabling attackers to manipulate game state, steal player credentials, or establish persistent access points within gaming networks. The vulnerability affects all players using affected versions of Call of Duty Modern Warfare 2, creating a widespread attack surface that could be leveraged for larger-scale campaigns targeting gaming communities. This weakness particularly threatens multiplayer gaming environments where players frequently form parties and join sessions, as the exploit can be triggered during normal gameplay operations without requiring special conditions or user interaction beyond joining an infected party.
Mitigation strategies for CVE-2019-20893 primarily focus on immediate patch deployment and network-level protection measures. Activision released security updates that addressed the buffer overflow vulnerability by implementing proper input validation and bounds checking within the PartyHost_HandleJoinPartyRequest function, effectively preventing malicious packet data from causing memory corruption. Network administrators should implement firewall rules and intrusion detection systems to monitor for suspicious joinParty packet patterns and limit outbound connections to gaming servers. Additionally, players should maintain updated game client versions and avoid joining parties from untrusted sources. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would enable attackers to execute arbitrary commands on compromised systems. Organizations should also consider implementing application whitelisting policies and regular security assessments to identify similar vulnerabilities in gaming software and network protocols that may present comparable risks to their gaming infrastructure and user base.