Two new strains of Trojan downloader have reached near epidemic proportions following an aggressive spamming campaign by hackers this week. Email security firm MessageLabs has intercepted over 54,000 copies of email-borne malware since early Thursday (7 July).
Both downloaders pose as email from the administrator of a user’s domain (sample below) in an attempt to dupe users into opening infected emails under bogus threats that their email account will be shut down otherwise. Once activated, the malicious code gives hackers backdoor access to compromised Windows PCs. The difference between the two downloaders is that they pull disparate additional malicious components (keylogger and backdoor) from two different webservers, reports anti-virus firm F-Secure.