Tag Archives: eBay

The Excel Pebble

Back on December 8th, 2005, I posted a comment about someone who created an eBay entry for a “Brand new Microsoft Excel Vulnerability”. The vulnerability was never sold via eBay, but may have traded hands through other means. For the most part, this incident faded into the background but I think this was the proverbial pebble thrown into the pond. Jump forward to yesterday, and Microsoft released an advisory covering multiple vulnerabilities in Excel. While chatting with one of the OSVDB manglers, I began to think out loud about why we would see so many Excel vulnerabilities released at once, and I think it became clear.

Remote Code Execution Using a Malformed Range – CVE-2005-4131
Remote Code Execution Using a Malformed File Format – CVE-2006-0028
Remote Code Execution Using a Malformed Description – CVE-2006-0029
Remote Code Execution Using a Malformed Graphic – CVE-2006-0030
Remote Code Execution Using a Malformed Record – CVE-2006-0031
Remote Code Execution Using a Malformed Routing Slip – CVE-2006-0009

Looking back at the original eBay entry, the poster said “all the details were submitted to Microsoft, and the reply was received indicating that they may start working on it. It can be assumed that no patch addressing this vulnerability will be available within the next few months.” The technical details released at the time stated “Microsoft Excel does not perform sufficient data validation when parsing document files. As a result, it is possible to pass a large counter value to msvcrt.memmove() function which causes critical memory regions to be overwritten, including the stack space.”

Note the CVE assignments for each of the vulnerabilities listed above. CVE-2005-4131 covers the eBay Excel 0-day. Shortly after that, we see CVE-2006-00xx assigned for five more Excel vulnerabilities and it is pretty clear what happened. Ollie Whitehouse, Peter Winter-Smith, Dejun, Eyas and Arnaud Dovi (via TP) all probably tried to find more details on the posted 0-day. In doing so, they discovered additional vulnerabilities in Excel and thankfully (for Microsoft) followed a responsible disclosure policy. This turned out to be an interesting byproduct of an amusing eBay listing.

Selling Vulnerabilities: Going once…

A couple days ago, “fearwall” created an eBay listing for a “Brand new Microsoft Excel Vulnerability”. I have mirrored a screenshot in case the listing is removed, which I expect it to be. One has to wonder if companies like iDefense or Tipping Point will bid, since they (and others) purchase vulnerabilities. Full text of the auction:

The lot: One 0-day Microsoft Excel Vulnerability

Up for sale is one (1) brand new vulnerability in the Microsoft Excel application. The vulnerability was discovered on December 6th 2005, all the details were submitted to Microsoft, and the reply was received indicating that they may start working on it. It can be assumed that no patch addressing this vulnerability will be available within the next few months. So, since I was unable to find any use for this by-product of Microsoft developers, it is now available for you at the low starting price of $0.01 (a fair value estimation for any Microsoft product).

A percentage of this sale will be contributed to various open-source projects.

Vulnerability De ion (read carefully, this is what you bid on).

Microsoft Excel does not perform sufficient data validation when parsing document files. As a result, it is possible to pass a large counter value to msvcrt.memmove() function which causes critical memory regions to be overwritten, including the stack space. The vulnerability can be exploited to compromise a user’s PC. It is feasible to manipulate the data in the document file to get a code of attacker’s choice executed when malicious file is opened by MS Excel. The exploit code is not included in the auction. You must have very advanced skills if you want to further research this vulnerability.

What will be delivered (at no extra charge):

The winning bidder must provide an e-mail address that accepts .xls attachments. Two xls files will be mailed to this e-mail address: one file is the original Microsoft Excel document, the other one is a copy of the same document modified to demonstrate the vulnerability. The demonstration merely triggers the exception causing Excel to crash. It does not do anything malicious. A detailed de ion of the vulnerability will be provided in the message body. At that time you can claim youself to be THE ONLY ONE IN THE WORLD possessing the knowledge about the vulnerability. Wow! Imagine that! (Well, not counting Microsoft, but I really doubt that they’ll share it with anyone.) It is up to you what to do with it, but you may not use it for malicious purposes – see terms and conditions below.

Special offers:

Microsoft representatives get 10% off the final price. To qualify, you MUST provide @microsoft.com e-mail address and MUST mention discount code LINUXRULZ during checkout.

Terms and conditions of the sale:

Your bid indicates that you agree to the following:

1. You may not use this information for malicious or illegal purposes. The information you receive is for educational and
research purposes only.
2. The seller reserves the right to refuse delivery to anyone (a full refund will be issued).
3. The seller will accept no responsibility for anything you do with this information.
4. The seller cannot be held liable under any circumstances.
5. Absolutely no refunds will be provided except for the reason mentioned above.

Disclaimers:

1. All trademarks are the property of their respective owners.
2. No proprietary software products were decompiled or reverse engineered.
3. All information advertised here was used and is to be used to promote the importance and advance the knowlegde in the field of the information security.
4. The seller does not encourage any illegal activity.

Even if this one is a joke, what is to stop this model of vulnerability selling and disclosure from occurring more often in the future? As MadSaxon joked about over two years ago, registering a 0-bay domain might be a fun business to start.

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