Microsoft's software security team is examining a new flaw in Word but is uncertain when it can release a patch for the vulnerability that opens a gateway for hackers to grab control of a victim's computer.
"Let me reassure everyone that the flaw is absolutely under investigation and we will release a patch or update as soon as we can," said Bruce Cowper, senior program manager, security initiatives, at Microsoft.
Microsoft normally releases updates and fixes on the second Tuesday of every month. The day has been known as Update Tuesday.
"This means the vulnerability could remain open for a month, or until the next periodic update comes," said David Frazer, director of technology services at tech security firm F-Secure.
Early last week, reports emerged that Microsoft Word programs sold from 2000 to 2006 contained a flaw that enabled hackers to attack a person's computer by sending the victim an e-mail with a Word document attachment containing a virus or malicious code.
Word 2007, which is currently available only to enterprise users, is not vulnerable to the attack.
The report closely followed news that hackers have released a file that circumvents the much vaunted security feature of Microsoft's recently released operating system Windows Vista.
Recently, Microsoft released several patches for flaws found in its products.
Cowper said Microsoft's probe could take several days because of a rigorous verification process. The work involves verification of the reported flaw, location of the areas affected by the flaw, and development and testing of a patch.
The new flaw might appear no more dangerous than previously disclosed flaws on Microsoft software, but its potential for damage is exacerbated by Word's popularity, according to one Canadian analyst.
"The situation becomes problematic because Word is such a ubiquitous program," said James Quin, senior research analyst for Info-Tech Research Group.
Because people are so familiar with the program, Quin said, they are less likely to question the origins of an e-mail containing a Word attachment.
Software vulnerabilities have created a thriving market for tech-savvy crooks that search for flaws and auction off this information to the highest bidder.
Until a patch is released the only thing computer users can do is to make sure their anti-virus software are updated and be wary about opening any unsolicited or suspicious e-mail.
Frazer of F-Secure said his firm has identified at least two Trojan viruses that are capable of exploiting Word's latest vulnerability.
One of the threats comes from the "cryptic" family of viruses that are able to deploy a malicious code by opening a backdoor entrance into a computer.
The other virus comes from a type called "tiny". These viruses are able to surreptitiously connect a victim's computer to website that can upload malware into the victim's computer, said Frazer. So far, Quin has not heard of any reports of this most recent flaw being exploited by malicious hackers, but he said it also possible that organizations that have been attacked are being "tight lipped" to prevent any negative publicity.