A fake phishing email making the rounds seemingly comes from Microsoft, but actually contains a “backdoor” trojan.

The email has a subject line that reads, “Security Update for OS Microsoft Windows” and supposedly came from the "Microsoft Official Update Center" at a domain named securityassurance[at]microsof[dot]com.

The message urges users to run an attached file to install an update that the email said will protect from the recipient from security threats and performance problems.

The malicious attachment is not a Microsoft update, but rather malware identified as “Trojan.Backdoor.Haxdoor,” which has the potential to turn computers into bots or enable an attacker to access corporate networks, Stephen Pao, vice president of product management at anti-spam provider Barracuda Networks, told SCMagazineUS.com Friday.

Marcus Sachs, director of SANS Internet Storm Center, told SCMagazineUS.com Friday that the organization received five reports from readers alerting them of the virus. Sachs later posted an alert about it.

Pao said this email took advantage of a combination of social engineering techniques. The malicious attachment used Microsoft terminology, and the bottom of the email contains a PGP signature block.

“They leveraged a very popular brand, targeted a broad base of users and most of those users have experienced in some form the need to update their Windows operating system,” Pao said. 

Sachs said companies restricting executables should be able to block the emails.


The malicious fake Microsoft email