Excel Patch Causing Calculation Errors
Microsoft admitted on Friday that a patch it released last week
is causing Excel 2003 to make some incorrect calculations.
"We have updated bulletin MS08-014
to provide additional information on a newly identified issue that causes Microsoft
Excel 2003 calculations to return an incorrect result when a real-time data
source is used," Microsoft's Security Response Center's Bill Sisk wrote
in a blog post
"The issue affects a specific scenario and may not affect you....Our teams are testing a fix and will release it once it meets our quality bar for broad distribution," he continued.
Microsoft offers some insight into the problem in Knowledge Base (KB) article
According to the KB, after the patch is applied on systems with "Microsoft
Office Excel 2003 installed, array-entered functions that contain a Visual Basic
for Applications (VBA) macro that refers to a real-time data source return an
incorrect value. The incorrect value is usually 0."
According to the very short KB item, for a current workaround, Microsoft recommends, "Run the function on each cell individually instead of on the array of cells."
The only other information available in the KB is that Microsoft is working
on a fix and will post more information as it becomes available.
The patch was released last week to stop
versions of Excel from allowing several types of remote execution attacks.