WinRAR 0-Day That Uses Poisoned JPG and TXT Files Under Exploit Since April

An anonymous reader quotes a report from Ars Technica: A newly discovered zeroday in the widely used WinRAR file-compression program has been under exploit for four months by unknown attackers who are using it to install malware when targets open booby-trapped JPGs and other innocuous inside file archives. The vulnerability, residing in the way WinRAR processes the ZIP file format, has been under active exploit since April in securities trading forums, researchers from security firm Group IB reported Wednesday. The attackers have been using the vulnerability to remotely execute code that installs malware from families including DarkMe, GuLoader, and Remcos RAT. From there, the criminals withdraw money from broker accounts. The total amount of financial losses and total number of victims infected is unknown, although Group-IB said it has tracked at least 130 individuals known to have been compromised. WinRAR developers fixed the vulnerability, tracked as CVE-2023-38831, earlier this month. "By exploiting a vulnerability within this program, threat actors were able to craft ZIP archives that serve as carriers for various malware families," Group-IB Malware Analyst Andrey Polovinkin wrote. "Weaponized ZIP archives were distributed on trading forums. Once extracted and executed, the malware allows threat actors to withdraw money from broker accounts. This vulnerability has been exploited since April 2023." It's recommended that you update to version 6.23 before using WinRAR again.

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