Recent findings have uncovered substantial vulnerabilities within a core networking library utilized by Valve for its online gaming infrastructure. These flaws could enable malicious actors to disrupt gaming sessions remotely and potentially seize control of third-party game servers.
Eyal Itkin from Check Point Research explicitly detailed the potential repercussions in an analysis published today. He stated, “An attacker could remotely crash an opponent’s game client to secure a win or employ a drastic ‘nuclear rage quit’ tactic, leading to a complete shutdown of the Valve game server.” More concerning is the potential for attackers to hijack third-party game servers to execute arbitrary code.
Valve, a prominent video game developer and publisher based in the United States, is well-known for its Steam platform, which distributes software for games such as Half-Life, Counter-Strike, and Dota, among others. The vulnerabilities, designated as CVE-2020-6016 through CVE-2020-6019, relate directly to the Game Networking Sockets (GNS) or Steam Sockets library. This open-source networking library facilitates a range of transport layer functionalities, combining UDP and TCP capabilities, encryption support, and reliable peer-to-peer communication.
These sockets are integrated into the Steamworks SDK available to third-party developers, putting both Steam servers and user-end game clients at risk. A particular flaw in the packet reassembly mechanism and an anomaly in C++’s iterator implementation create opportunities for attackers to send malicious packets to target servers, triggering a heap-based buffer underflow that could lead to server crashes.
After disclosing these vulnerabilities to Valve on September 2, 2020, timely updates were implemented in game clients and servers by September 17. However, as of December 2, Check Point noted that some third-party developers had yet to address the vulnerabilities in their game clients.
Itkin pointed out the heightened gaming activity during the coronavirus pandemic, stating, “Given the millions engaged in online gaming, even minor security issues can escalate into serious threats for both the gaming industry and players’ privacy. The vulnerabilities identified could have facilitated widespread exploitation, with attackers gaining control over numerous gamer systems without detection.”
Selected online platforms represent significant targets for cybercriminals. The high volume of users creates an environment where the effectiveness of well-developed exploits significantly amplifies. Check Point confirmed that players using Valve’s games via Steam are protected due to the applied fixes, yet players of third-party games must ensure they have received critical updates to mitigate risks associated with these vulnerabilities.