Advisory - Firefox Denial of service (Keygen)

• [TZO 27-2009] Firefox Denial of Service (Keygen)
  

I have received interesting and mixed feedback from posting the above "bug".

• First I'd like to clarify that a vulnerability is measured by the impact it causes, not how easy it is to find it and not by how technically challenging a vulnerability is.
  
  
• Secondly, vendors appear to not like it but remotely controlling the availability of an application is a security issue. It is the A in the CIA concept. If you are interested in that discussion I wrote a small blog rant about the "Denial of service is not a security issue" mindset of certain vendors.
  
  
  
  
• Third, I just hand over the facts, nothing more. If vulnerability database maintainers do not perceive Denial of service conditions in browsers as a security issue, they would not add it to the database, and yet they do. Doesn't prove anything but underlines my reasoning.
  
  
• Is this bug a vulnerability? - yes. Is is critical ? Clearly no. Stop seeing the world in Black or White. Something can be a vulnerability and still not be critical for the general public. However make no mistake, some bugs that are (for example) rated medium can become critical for certain companies that use the products in certain ways or critical parts of an infrastructure rely on that particular application.
  
  
• This is the reason I give no risk rating, what for ? I can't assess the risk an customer runs in specific environments when this vulnerability hits the product, I have no way to assess the risk whatsoever. I think it is highly misleading to have a vendor rate risk for a vulnerability. What I give is a description of the impact, with an description of the impact the customer of that product is actually able to assesses the risk, he is the only one that can.
  
  
• To illustrate this point take the bug above and think about several scenarios where this bug might actually pose a problem. Have one ? Fine. I have one too; what about for example Internet Kiosk vendors ? i.e the terminals at airports or cities that give access to the internet. Browse to the PoC and the terminal can no longer be used - so, for terminals offering pay for access service, this might mean actually income loss. (I am aware that some "restart" the whole OS or the envrionment periodicaly to clean up the mess left behind) Still I think you'll get the point here, there are a lot more scenarios like this.
  
  There is more then the typical End-user at home sitting before his pc that kills the process and restarts firefox.
  
  
• During my years doing security consultancy, one of the most astonishing things I learned is the immense variety of how applications are used by different companies. There is no way to summarise risk.