Snort mailing list archives
Question regarding distances after a byte_jump...
From: evejou <girl () techn0ev3 net>
Date: Thu, 16 Dec 2010 17:54:19 -0500
Hi, I was trying to write a signature for Snort v2.6.1.5. I have a question about using the distance/within tags after a byte_test, if that's even proper use for it. Say there's a packet that looks kind of like this: MM MM OO OO OO [....] TT XX XX AA AA ... (MM -- magic number) (OO -- offset value that points to the TTs; this offset counts from the beginning of the file) (XX XX -- 2 bytes that I don't care about) I was trying to figure out where the pointer would be after a byte_jump, so I tried to write the following to see if it would trigger: *content:"|MM MM|"; byte_jump:3,0,relative,from_beginning,post_offset 2; content:"|AA AA|"; distance:0; within:2;* I noticed that this didn't trigger, but that it did when I removed the "within:2" part. And then I tried the following: *content:"|MM MM|"; byte_jump:3,0,relative,from_beginning,post_offset 2; content:"|OO OO OO|"; distance:0; within:3;* and this triggered as well. My first question is whether this is expected behavior (or am I doing something wrong?), and adjunctly to that, how I could get a hit on that second content tag (the |AA AA| part)... Thanks, Alice -- --- girl () techn0ev3 net Finché c'è vita, c'è speranza. As long as there is life, there is hope.
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Current thread:
- Question regarding distances after a byte_jump... evejou (Dec 16)
- Re: Question regarding distances after a byte_jump... evejou (Dec 16)
- Re: Question regarding distances after a byte_jump... Joel Esler (Dec 16)
- Re: Question regarding distances after a byte_jump... evejou (Dec 16)
- Re: Question regarding distances after a byte_jump... Joel Esler (Dec 16)
- Re: Question regarding distances after a byte_jump... Joel Esler (Dec 16)
- Re: Question regarding distances after a byte_jump... evejou (Dec 16)