On Wed, 2004-12-29 at 17:56 -0500, J. Oquendo wrote: <snip> > III SOLUTION > Symantec could rewrite their updates to include a timer, or check via > atomic clock. Other options include informing their customers not to > commit the evil act of modifying the dates on their computers. <snip> Inadequate solutions: 1. Rewrite the updates to include a timer - the downloaded update could be modified and the timer changed. Even if the update is encrypted or checksum'd the decryption algorithm/key would have to be in the users product so could easily be reverse engineered. 2.Check date via an atomic clock - sticking a fake IP for the clock domain name into the hosts file or creating a fake local response to the time request would overcome this. The true solution would be a completely server side check, such as a user/pass combination with the details stored on Symantec's servers and the downloads blocked by http authentication using these credentials (which expire at subscription end). The only real work arounds for this are to compromise the account of another user or the servers themselves. When auditing and disclosing a bad solution in a product it's a good idea to research your solution to ensure it doesn't contain easily exploitable vulnerabilities. Nonetheless Symatec might want to address this in order to keep that stock price up. :-) With Regards.. Barrie Dempster (zeedo) - Fortiter et Strenue http://www.bsrf.org.uk [ gpg --recv-keys --keyserver www.keyserver.net 0x96025FD0 ]
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