Vulnerability identifier: #VU48927

Vulnerability risk: High

CVSSv3.1: 8.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-6017

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Game Networking Sockets
Client/Desktop applications / Games

Vendor: Valve Software

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input within the SNP_ReceiveUnreliableSegment(), when configured to support plain-text messages. A remote attacker can send specially crafted  packets to the application, trigger out-of-bounds write and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Game Networking Sockets: 1.0.0 - 1.1.0

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External links
http://github.com/ValveSoftware/GameNetworkingSockets/commit/e0c86dcb9139771db3db0cfdb1fb8bef0af19c43
http://research.checkpoint.com/2020/game-on-finding-vulnerabilities-in-valves-steam-sockets/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.