CVE-2021-34170: Dark Souls III RCE Vulnerability

CVE-2021-34170 Overview

CVE-2021-34170 is a critical remote code execution vulnerability affecting Bandai Namco FromSoftware Dark Souls III. This vulnerability allows remote attackers to execute arbitrary code on affected systems running the game. The vulnerability can be exploited over the network without requiring any authentication or user interaction, making it particularly dangerous for players engaged in online multiplayer sessions.

Critical Impact

Remote attackers can execute arbitrary code on vulnerable Dark Souls III installations, potentially compromising player systems during online gameplay sessions.

Affected Products

• FromSoftware Dark Souls III (all versions)

Discovery Timeline

• 2021-06-15 - CVE CVE-2021-34170 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-34170

Vulnerability Analysis

This remote code execution vulnerability in Dark Souls III represents a significant security risk for players engaging in online multiplayer functionality. The vulnerability allows attackers to remotely execute arbitrary code on target systems through the game's network protocol. Given the network-accessible nature of this vulnerability combined with the absence of authentication requirements, attackers can potentially compromise any player connected to online services.

The vulnerability gained significant attention within the Dark Souls community, as documented in community discussions regarding potential PC security exploits spreading through online play.

Root Cause

The root cause of this vulnerability stems from improper handling of network data within the Dark Souls III game client. The game's network protocol fails to properly validate or sanitize incoming data from remote peers during multiplayer sessions, allowing malicious actors to inject and execute arbitrary code on connected players' systems.

Attack Vector

The attack vector for CVE-2021-34170 is network-based, requiring no privileges or user interaction. An attacker can exploit this vulnerability by:

1. Connecting to the same online session or invading another player's game world
2. Sending specially crafted network packets to the target player
3. Triggering the vulnerability to execute arbitrary code on the victim's system

The exploitation occurs entirely through the game's online functionality, meaning any player with online play enabled is potentially at risk.

Detection Methods for CVE-2021-34170

Indicators of Compromise

• Unexpected game crashes or abnormal behavior during online multiplayer sessions
• Unusual network traffic patterns from the Dark Souls III process
• Suspicious process spawning or file system modifications originating from the game executable
• Abnormal memory consumption or CPU usage by the game client

Detection Strategies

• Monitor network traffic for anomalous packets being sent to or from Dark Souls III processes
• Implement endpoint detection rules to identify suspicious child processes spawned by the game executable
• Deploy application behavior monitoring to detect unauthorized code execution patterns
• Review system logs for evidence of exploitation attempts during online gaming sessions

Monitoring Recommendations

• Enable detailed logging for the Dark Souls III application and associated network connections
• Configure endpoint protection solutions to monitor for suspicious activity from gaming processes
• Implement network segmentation to isolate gaming systems from sensitive resources
• Monitor for community reports and vendor communications regarding active exploitation

How to Mitigate CVE-2021-34170

Immediate Actions Required

• Disable online functionality in Dark Souls III until a patch is applied
• Play the game in offline mode to eliminate the network attack vector
• Ensure endpoint protection software is active and updated when playing online games
• Monitor FromSoftware and Bandai Namco communications for security updates

Patch Information

Players should monitor official FromSoftware and Bandai Namco channels for security patches addressing this vulnerability. No specific patch information was available at the time of publication. It is recommended to keep the game client updated to the latest version and verify that automatic updates are enabled through the game distribution platform (e.g., Steam).

Workarounds

• Launch Dark Souls III in offline mode by disabling network features in the game settings
• Use firewall rules to block Dark Souls III network connections when playing solo content
• Consider using password-protected private sessions when playing with trusted friends
• Avoid accepting summons or invasions from unknown players until the vulnerability is patched

# Example: Block Dark Souls III network access using Windows Firewall
netsh advfirewall firewall add rule name="Block Dark Souls III Outbound" dir=out program="C:\Program Files (x86)\Steam\steamapps\common\DARK SOULS III\Game\DarkSoulsIII.exe" action=block