An ActiveX control in Micro$oft Office 2000 named "Office UA Control" used to script demonstrations for Office 2000 Help can be used to script almost any action that a user could perform from the keyboard, an advisory from L0pht Heavy Industries says.
The ActiveX control is "incorrectly marked as 'safe for scripting,'" Micro$oft says. "A malicious Web site operator could use the control to carry out Office functions on the machine of a user who visited his site," the company adds.
Actions can be scripted from any HTML page viewed with active scripting enabled, including both Internet Explorer and Outlook, L0pht reports.
L0pht has a demonstration which will start Micro$oft Word, create a UA control and re-point a table frame to a word document URL with a macro, which will run without prompting. The demo is available here.
The flaw could "permit the construction of a worm of unparalleled devastation, as it would be able to turn off macro virus protection and 'script' it's way to all of the people in your address book," L0pht says.
Micro$oft has released a patch and a security bulletin related to the vulnerability. Not surprisingly, the company makes no mention of the worm potential of this little gem, following as it does so closely on the heels of the Love Bug.
In the bulletin, Micro$oft gives shouts to Dildog at L0pht, who brought the flaw to their attention. A link is provided from there to the Micro$oft shouts policy page, where the company reminds us all that "the discoverer of a security vulnerability has an obligation to give the vendor an opportunity to correct the vulnerability before publicly disclosing it."
"When you see a security professional acknowledged in a Microsoft Security Bulletin, it means that they reported the vulnerability to us confidentially, worked with us to develop the patch, and helped us disseminate information about it once the threat was eliminated. They minimized the threat to customers everywhere by ensuring that Microsoft could fix the problem before malicious users even knew it existed," the company gushed.
Anyone care for a tissue? ®