The unusual route to vulnerability profit-taking was squashed by eBay after the listing--offered by someone only identified as "fearwall"--was bid up to just under $60.
According to the since-yanked listing, the zero-day vulnerability in Excel had been reported to Microsoft on Tuesday, Dec. 6. "All the details were submitted to Microsoft, and the reply was received indicating that they may start working on it," wrote the seller. "It can be assumed that no patch addressing this vulnerability will be available within the next few months."
The unpatched vulnerability is in the way that Excel, the popular spreadsheet included in all editions of Microsoft's Office suite, validates the data in some worksheets when it parses files.
"The vulnerability can be exploited to compromise a user's PC," claimed the seller.
He also took several potshots at Microsoft, saying that the opening bid of $.01 was "a fair value estimation for any Microsoft product" and offered a 10 percent discount to any Microsoft employee who mentioned the discount code "LINUXRULZ."
A spokeswoman for Microsoft confirmed that the listing on eBay was for a real bug in Excel. "The Microsoft Security Research Center has not been made aware of any attacks attempting to use the reported vulnerability or customer impact at this time, but [it] will continue to investigate the public reports to help provide additional guidance for customers," she said in an e-mail to TechWeb.
The spokeswoman also said that Microsoft's researchers were investigating the vulnerability, and might (or might not) release either a fix or a security advisory in the future.
"The company is working with eBay to determine the appropriate course of action," she also said.
[Update, Monday, Dec. 12; 12:45 pm: The original article included the phrase "against the seller" after the preceding quote, outside of the quotation marks. That was incorrect; Microsoft is working with eBay to determine a general course of action to protect its customers. ]