Two separate Internet security firms are warning customers that Microsoft Office users are being specifically targeting in these attacks.On Friday, Web security firm Websense warned in this blog post that Microsoft customers searching on Microsoft's site, office.microsoft.com, may get results that send theme to a rogue anti-virus Web site.

From Websense's alert:

Users looking for information related to help with Office products on Microsoft's own site are being targeted. Users may be unaware that, when they type in search queries on the site, Microsoft scours its own Web site for results, but also pulls in results from the broader Web. As the URL for the search results begins with http://office.microsoft.com, this is particularly troubling for users who trust sites simply because of their reputation.

The malicious URL is a redirect to a very real-looking virus scan and warning page presented by a Rogue AV program (SHA1: 6489c54e30af18801a9e83a5855fa639f3bae0b8). The executable used in the exploit is currently recognized by 1 of the 41 AV engines on Virus Total.

Also, Websense has a video that goes into some depth on the attack.

I found this attack to be very interesting. We already know that malicious Search Engine Optimization (SEO) is becoming an increasingly problem on the broader Web - but I had yet to see SEO being used to target the customers actually using a vendor's Web site for search.

In an unrelated attack (except for once again targeting Microsoft customers) anti-spam vendor Red Condor issued an alert informing users that:

an aggressive spear phishing email campaign inviting recipients to "apply a new set of settings" to their mailboxes because of a recent "security upgrade" of their mailing service. An embedded link in the email connects users to a web site that appears to be a Microsoft® Office Outlook® Web Access page, including official Microsoft® and Microsoft Office logos. On the page, users are directed to "download and launch a file with a new set of settings for your e-mail account." The executable is actually a Zbot Trojan virus similar to Trojans distributed in recent H1N1 and Facebook phishing attacks.