MS patches insecurity trio
Word, SQL, Help
Another bundle of three security issues in Microsoft products came out this week. Among them is a nasty bug in Windows-XP Help Center allowing the deletion of entire directories, as we reported a few weeks ago.
A malicious file request, the syntax of which resembles a URL, can be embedded in a Web page or an HTML e-mail. MS rolled the fix silently into SP-1 without making a public announcement at the time. The hole was discovered by Shane Hird of Distributed Systems Technology Centre, who first reported it to MS on 25 June 2002. Now there is apparently a separate patch for the issue, and MS has come forward with the dirt. In typical fashion the company also treats the announcement with far-fetched, PR-driven stretchers and face savers, as we can see from their list of 'mitigating factors'.
The vulnerability can only be exploited with "some degree of user interaction," MS says. "Even in the most attacker-favorable case, the Help and Support Center window would appear unexpectedly and the file deletion could not occur until the user responded. (Even selecting Cancel, though, would enable the deletion to occur). If the user killed the process rather than responding, the deletion could not occur."
That's right, MS considers this a mitigating factor. But wait, there's an even more desperate one: "For an attack to be successful, the user would need to visit a Web site under the attacker's control or receive an HTML e-mail from the attacker."
Which is another way of saying the deletions don't occur spontaneously.
Next, there's a bug in SQL Server allowing privilege escalation which can be exploited locally and remotely if Web tasks are used. A stored procedure fails to set permissions properly when executed and runs with the privileges of the SQL Server. An un-privileged user can run, delete, insert and update Web tasks, according to MS. The flaw affects SQL Server 2K, SQL Server 7, Data Engine 1.0 and Desktop Engine 2K. It was discovered by David Litchfield of NGSS Software and reported to MS on 23 August. Additional details and patches are available here.
Finally, a bit of a stuff up with Word and Excel which can compromise user privacy but isn't harmful to data and offers no system privileges to an attacker. The flaw affects Word 97, Word 2000, Word 2002, Excel 2002 and Word for Mac. It also affects Outlook and OE where Word is used as the editor.
Field codes, often used to automate the insertion of boilerplate in documents, can be perverted to allow an attacker to use external updates to steal data from other files on a victim's system. In a typical scenario, the attacker sends a malicious document to a victim, and entices the victim to open it and return it. Because of the amount of user interaction needed, the fact that the attacker needs to know the name and location of the file he wants to steal, and the fact that field codes can easily be viewed by the victim, it is not thought to be a terribly serious threat. MS has devised patches, available here.