Microsoft’s flagship word processor has a security flaw that could allow the theft of computer files by ”bugging” a document with a hidden code, the company disclosed on Thursday. It was exploring how to fix the problem and whether to extend the repair to an older version of the software still used by millions.
The attack begins when a bugged document goes out, usually with a request to be revised and returned to the sender – a common form of daily communication. When the document is changed and sent back, the targeted file accompanies it.
”It has the potential of allowing people to get at data that they are explicitly not allowed to get to,” said Woody Leonhard, who has written books on Microsoft’s Word and Office software. The flaw would most likely occur in the workplace, where Word is the most prominent word processing program. Potential targets for theft are sensitive legal contracts, payroll records or e-mails, either from a hard drive or computer network, depending on the victim’s access to files.
”The issue appears to affect all versions of Microsoft Word,” Microsoft said in a statement.
”When the investigation is completed, we will take the action that best serves Microsoft’s customers.”
Word 97, an earlier version of the program, is most susceptible to the attack. But Word 97 will not be repaired because Microsoft no longer provides support it, the company said.
A research firm reported in May that about 32% of offices have copies of Word 97 running, according to a survey of
1 500 high-tech managers worldwide.
Analyst Laura DiDio of the Yankee Group said the companies are taking a risk by using such old software. But she said Microsoft should correct the problem because of its severity. ”These are paying customers,” DiDio said.
Leonhard said Word 97 users ”bought the package with full faith in Microsoft and its ability to protect them from this kind of exploit.”
Word 97 users may be able to get some help from through Microsoft’s telephone tech support, company representative Casey McGee said. But, referring to Microsoft engineers, McGee said ”there’s only so far back they can go.”
The flaw involving Word 97 was discovered by Alex Gantman of cellular phone company Qualcomm and was released on the Internet last month.
An attacker only has to place hidden codes in a Word document, which is sent to a would-be victim with a request for a response. If the recipient has Word 97 and revises the Word document, any file sought by the attacker will be hidden inside the Word document and sent back to the attacker.
If the intended target uses Word 2000 or 2002, the most recent versions, the attack will only work if the Word document is printed first before a reply goes out to the attacker.
After seeing Gantman’s work on a public security e-mail forum, Leonhard found a similar flaw that affects recent Word versions even when a document is not printed. In this case, the stolen file is visible within the document, although the attacker can make it hard to find.
Microsoft says that in both security flaws, an attacker would have to know the exact file name to be stolen and its location. But many critical files – an address book or saved e-mails, for example – are usually in obvious or predictable places on every Microsoft Windows computer.
Microsoft suggests users view hidden codes in every document they open. In Word 2002, the latest version, that can be done by selecting tools, options, then checking the ”field codes” box. Many companies, however, use such codes for legitimate and harmless purposes.
Leonhard said that if an attacker tries to steal a very large file, the victim might notice it when saving or e-mailing the bugged document. A smaller file might not get that attention. ”It’s very much dependent on the greed of the person fishing for a file,” Leonhard said. – Sapa-AP