Trojan-Dropper:OSX/Revir.A poses as PDF to open botnet backdoor backdoor. Finnish security firm F-Secure says it lays the groundwork for sophisticated attacks on Macs. Trojan doesn’t really do anything yet, but it could be used for more sophisticated attacks. 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. Users who might fall victim to this attack aren’t likely to see many ill effects for the time being.
Source: https://thehackernews.com/2011/09/mac-trojan-poses-as-pdf-to-open-botnet.html