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Res Timing File Enumeration Without JavaScript in IE7.0

I’ve been meaning to post this since Blackhat last year, but I just finally got around to posting a working example. Using David Byrne’s res:// timing trick and a hybrid of Jeremiah’s META refresh blocking I was able to do the same thing David was but without JavaScript. Oh how funky it is though!

Here’s the demo (only works in IE7.0). The timing is large enough so that you can actually see a difference (varies between a 5 and 15 second difference for me per link - for reasons I am still unsure of). But it’s a big enough difference that it should be possible to measure the file’s presence. The hard part is keeping it going without a user noticing that their browser locked up on them for the many seconds required to run. Pretty funky demo, and normally I’d probably set a cookie to keep the data but I got bored of writing the demo since I don’t think it’s especially practical. But you get the idea.

In other news, I should also mention that I got back from the Minnesota OWASP meeting. I was really surprised to see how many people came out to see me (probably 75 or so). All really nice people and I was impressed by Kuai and the entire setup. Very nicely done. I think my slides will be posted today or tomorrow. I guess Bruce Schneier spoke there the month before I did, so these guys definitely have got their eye on the heavy hitters for those of you on the speaking circuit. I also spoke on Minnesota Public Radio as well, which was kinda fun. I hope it continues to grow!

I missed Schmoocon and DC Blackhat but here is the unofficial list of my upcoming cons: Source Boston (leading a panel), RSACon 2008 (just visiting), TRISC (speaking), Secure360 (speaking - unconfirmed), Super Secret SANS Conference to be talked about at a later date (speaking), OWASP Denver (speaking - unconfirmed), World OWASP NYC 2008 (speaking). So yah, busy busy busy…

One Response to “Res Timing File Enumeration Without JavaScript in IE7.0”

  1. Phil Says:

    Finally a post! ;)