Mac trojan poses as PDF to open botnet backdoor
Malware continues to be a minimal threat to most Mac users, but that doesn’t mean attackers aren’t constantly trying to come up with new ways to steal information or turn users’ machines into botnet drones. The latter appears to be the case with a new Mac trojan posing as a PDF file, discovered by security researchers at F-Secure.
The malware in question has been identified as Trojan-Dropper:OSX/Revir.A, which installs a backdoor, Backdoor:OSX/Imuler.A, onto the user’s Mac. Currently, however, the backdoor doesn’t communicate with anything. The command-and-control center for this particular malware is apparently a bare Apache installation, which has been sitting at its current domain since May of this year. Because of this, users who might fall victim to this attack aren’t likely to see many ill effects for the time being, but that could change if the files end up spreading to a wider audience.
As mentioned earlier, this trojan spreads by masking itself as a PDF, which displays a Chinese-language document on the screen in an attempt to hide its background activity. This isn’t a new strategy on the surface, as F-Secure notes, but some deeper digging indicates that it might be stealthier than its Windows counterparts.