Although the details are close to a minimum, reports regarding a second zero-day vulnerability affecting Microsoft Word are intensifying. As yet, Microsoft has failed to deliver additional information except for a list with the impacted software versions. According to Microsoft Word 2000, Word 2002, Word 2003 and the Word Viewer 2003 are all open to exploits.

Secunia has already labeled the vulnerability as extremely critical, as it allows for remote code execution, and stated that it is actively exploited. "A vulnerability has been reported in Microsoft Word, which can be exploited by malicious people to compromise a user's system. The vulnerability is caused due to an unspecified error when processing Word documents. No more information is currently available," explained Secunia.

"Word 2007 is not affected by the vulnerability. From the initial reports and investigation we can confirm that the vulnerability is being exploited on a very, very limited and targeted basis. We're tracking this issue through our Software Security Incident Response Process and as always, we'll continue to monitor the situation and provide updates should the situation change or we become aware of new information," stated Scott Deacon from the Microsoft Security Response Center Team.

As far, the Redmond Company has not provided either a patch or a workaround to address the vulnerability. But is seems that the exploits are associated with social engineering schemes. In this context, users should avoid executing Word documents that come from untrusted or unknown sources. McAfee has warned that attacks involve the PWS-Agent.g Trojan horse, malware that is designed to harvest passwords from Internet Explorer, Firefox, and POP3 e-mail clients.