Fake Windows patch e-mail leads to Trojan horse attack

Computerworld - Messages insisting that users install a just-released Microsoft Corp. security update are bogus and actually lead to a site that plants malicious code on PCs, several security companies warned today.

The spam, which touts "Microsoft Security Bulletin MS07-0065 -- Critical Update" as its subject and appears to come from "update@microsoft.com," claims users should download a June 18 security patch and provides a link to a URL that looks legit.

"A new 0-day vulnerability has appeared in the wild," the message reads. "The vulnerability affects machines running MICROSOFT OUTLOOK and allows an attacker to take full control of the vulnerable computer if the exploitation process is succesfull [sic]." It goes on to boast that 100,000 PCs have been hijacked so far by unnamed malware exploiting the bug.

However, the link takes users to one of several different attack sites that download a Trojan horse to the machine. "Security bulletins from Microsoft describing vulnerabilities in their software are a common occurrence," noted Graham Cluely, a Sophos PLC analyst, in a statement today. "[But] by using people's real names, the Microsoft logo and legitimate-sounding wording, the hackers are attempting to fool more people into stepping blindly into their bear trap."

The SANS Institute's Internet Storm Center and Symantec Corp.'s DeepSight threat network have also issued alerts on the fraudulent messages.

Playing the legitimacy card is an important "scam-spammer" technique, James Blascovich, a professor of psychology at the University of California, Santa Barbara, said yesterday in a just-released paper on the mind games attackers play to persuade people that it's safe to open suspicious e-mail. The fake security alert, for example, refers to "Genuine Microsoft Software," a phrase the company itself heavily promotes; uses the recipient's first name in the body of the message; and includes a purported product registration key.

Alert users, however, will be immediately suspicious of the message -- and not just because of the typical-for-spam misspellings -- but because it labeled the update "MS07-0065." So far this year, Microsoft has only reached MS07-035 in its numbering system.