Let’s just get to the point: if you get an email that has an excel spreadsheet attached to it, make sure not to open it. This is how the zero-day attack works. People open the malicious spreadsheet and host malicious Office files on the web so when a user opens them, hackers can gain remote control of their computers.

Microsoft is warning of an Excel-focused zero-day attack that affects several versions of its Office software, including one for Macs.

In its security advisory issued Friday, Microsoft warns people of a “very limited” zero-day attack that takes advantage of vulnerabilities in the Excel spreadsheet program.

The “extremely critical” Excel vulnerabilities are found in Microsoft Office 2000, Office 2003 and Office XP, as well as in Office 2004 for computers running Apple’s Mac OS, according to a separate advisory from security company Secunia.

Attackers are sending e-mails with malicious Excel attachments and are hosting Web sites that house Office files that attempt to take advantage of the security flaws, according to Microsoft. Once an attacker exploits the vulnerabilities, they can gain control of a person’s system remotely.[more]

Tags: Malware, Bugs