Mac version Transmission contained malware for the second time

The official version of bittorrent client Transmission for OS X has been infected with malicious code for the second time. This time, users are infected with the Keydnap malware, which steals data from the keychain. Presumably, the malware was present on August 28 and 29.

Security firm ESET discovered the presence of Keydnap in Transmission v2.92 and notified the developers of the software. According to the researchers, the bittorrent client was immediately replaced by a clean version, but the infected client would have been online on August 28 and 29. Transmission has not yet responded to the incident and the website is offline at the time of writing.

The Keydnap malware present in the software was discovered by ESET in early July. The malware can be used to steal password data from the keychain and acts as a backdoor. At the time, there was still uncertainty about how the malware was spread.

It is the second time that the Mac version of Transmission has contained malware. In March, it turned out that version 2.90 of the app was infected with the ransomware KeRanger. At the time, the infected software was downloaded by 6,500 people.

It is not yet clear how the attackers gained access to Transmission’s web server to infect a signed version of the app with their malware. The developer said it would provide details about the attack after the first incident, but so far it hasn’t happened.