CVE-2020-7952 in Dota
Summary
by MITRE
rendersystemdx9.dll in Valve Dota 2 before 7.23f allows remote attackers to achieve code execution or denial of service by creating a gaming server and inviting a victim to this server, because a crafted map is affected by memory corruption.
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Analysis
by VulDB Data Team • 03/26/2024
The vulnerability identified as CVE-2020-7952 affects the rendersystemdx9.dll component within Valve Dota 2 client software versions prior to 7.23f. This represents a critical memory corruption flaw that enables remote code execution and denial of service conditions through a specifically crafted gaming map file. The vulnerability manifests when a malicious attacker creates a gaming server and invites a victim to join, exploiting the improper handling of map file data during the rendering process. The technical implementation involves the manipulation of memory structures within the DirectX 9 rendering system, which is a core component responsible for graphics processing in the game client. This flaw exists at the intersection of software security and graphics rendering, where improper input validation leads to memory corruption that can be leveraged for arbitrary code execution. The vulnerability is classified as a memory corruption issue that aligns with CWE-121, which encompasses unsafe array access and memory management flaws, and can be categorized under ATT&CK technique T1059.007 for command and scripting interpreter usage in the context of exploitation.
The operational impact of this vulnerability extends beyond simple denial of service to encompass full system compromise capabilities. When a victim joins a maliciously crafted game server, the specially designed map file triggers the memory corruption within rendersystemdx9.dll, potentially allowing attackers to execute arbitrary code with the privileges of the affected user. This represents a significant threat vector in gaming environments where users frequently join servers hosted by others, as the attack can be delivered through legitimate game functionality without requiring additional malicious software installation. The exploitability factor is particularly concerning given that it requires minimal user interaction beyond accepting an invitation to join a game server, making it a prime target for social engineering campaigns within gaming communities. The vulnerability affects the rendering subsystem specifically, which means it operates at a level where graphics processing occurs, potentially allowing attackers to bypass traditional security controls that focus on network-level or application-level protections.
Mitigation strategies for CVE-2020-7952 primarily involve immediate software updates from Valve to address the memory corruption issue within rendersystemdx9.dll. Users should ensure their Dota 2 client is updated to version 7.23f or later, which contains the necessary patches to prevent the exploitation of this vulnerability. Network administrators and security teams should implement monitoring for suspicious gaming server invitations and consider implementing application whitelisting policies that restrict execution of unsigned or untrusted game content. The patching process addresses the root cause by correcting the memory handling routines in the DirectX 9 rendering subsystem, specifically by implementing proper bounds checking and memory validation before processing map files. Organizations should also consider deploying network segmentation to limit the potential impact of successful exploitation, as the vulnerability requires network connectivity to the game server and the user must actively participate in the malicious game session. Security awareness training should emphasize the risks of accepting invitations to unknown or untrusted gaming servers, as this vulnerability demonstrates how legitimate gaming features can be abused for malicious purposes. The fix implemented by Valve likely includes enhanced input validation for map file processing, proper memory allocation and deallocation routines, and improved error handling within the rendering system to prevent the corruption conditions that enabled remote code execution.