An not known menace actor designed malicious game modes for the Dota 2 multiplayer online battle arena (MOBA) video clip sport that could have been exploited to create backdoor access to players’ units.
The modes exploited a substantial-severity flaw in the V8 JavaScript engine tracked as CVE-2021-38003 (CVSS rating: 8.8), which was exploited as a zero-day and tackled by Google in October 2021.
“Given that V8 was not sandboxed in Dota, the exploit on its possess allowed for remote code execution versus other Dota gamers,” Avast researcher Jan Vojtěšek mentioned in a report published last week.

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Adhering to accountable disclosure to Valve, the activity publisher shipped fixes on January 12, 2023, by upgrading the edition of V8.
Recreation modes are effectively custom made capabilities that can either augment an present title or supply wholly new gameplay in a method that deviates from the standard principles.
Although publishing a tailor made activity manner to the Steam retailer includes a vetting system from Valve, the malicious activity modes learned by the antivirus vendor managed to slip by the cracks.
These video game modes, which have because been taken down, are “check addon plz ignore,” “Overdog no annoying heroes,” “Personalized Hero Brawl,” and “Overthrow RTZ Edition X10 XP.” The danger actor is also said to have revealed a fifth recreation method named Brawl in Petah Tiqwa that did not pack any rogue code.
Embedded inside of “examination addon plz overlook” is an exploit for the V8 flaw that could be weaponized to execute personalized shellcode.
The three many others, on the other hand, acquire a additional covert tactic in that the malicious code is designed to reach out to a distant server to fetch a JavaScript payload, which is also probably to be an exploit for CVE-2021-38003 considering that the server is no extended reachable.
In a hypothetical attack situation, a participant launching 1 of the over sport modes could be focused by the menace actor to reach remote accessibility to the infected host and deploy further malware for further exploitation.
It truly is not right away recognised what the developer’s finish aims were being behind producing the recreation modes, but they are not likely to be for benign exploration needs, Avast famous.
“Very first, the attacker did not report the vulnerability to Valve (which would commonly be regarded a nice issue to do),” Vojtěšek reported. “Next, the attacker attempted to cover the exploit in a stealthy backdoor.”
“Regardless, it’s also feasible that the attacker failed to have purely malicious intentions either, considering the fact that such an attacker could arguably abuse this vulnerability with a considerably more substantial influence.”
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Some areas of this write-up are sourced from:
thehackernews.com