Snort mailing list archives
Re: How to detect drive letters accessed?
From: John Sage <jsage () finchhaven com>
Date: Thu, 17 Jan 2002 20:28:24 -0800
I kinda lurked on this thread until tonight I remembered an entirely different tool you might use to set up a rule that covers a range of drive letters (or any other complex syntax...)
The tool is ngrep (network grep), see: http://www.incidents.org/papers/ngrep.php and: http://ngrep.sourceforge.net/ngrep allows you to make complex regex expressions and use them to watch packet contents, kinda like snort and/or tcpdump but on steroids..
To quote from the incidents.org article:"...The problem comes when we don't have a fixed series of characters to match against.
The November 2001 wu-ftpd exploit used the fact that a sequence of whitespace, a tilde, optional characters, a left curly brace, and any other characters without a matching right curly brace would crash wu-ftpd, allowing a buffer overflow exploit to take over.
Because of the possibility of additional characters and the requirement that the second block of characters not contain a "}", we need to use something stronger than fixed strings..."
- John -- The web page you seek cannot be found here: countless others await
-----Original Message----- From: snort-users-admin () lists sourceforge net [mailto:snort-users-admin () lists sourceforge net]On Behalf Of Sheahan, Paul (PCLN-NW) Sent: Wednesday, January 16, 2002 5:20 PM To: Snort List (E-mail) Subject: [Snort-users] How to detect drive letters accessed? Running Snort 1.8.1 B78 on RH Linux 7.0. Using Snort, I am trying to detect when someone accesses a certain drive on one of my servers. For example if I have a server that has a drive letter K: that no one from the outside world should see or be accessing, I'd like to create a rule in Snort that checks for "K:\" in a packet. The trouble is, I can't just create a rule that searches for "K:\" because the rule doesn't work. I think the colon screws it up or something. Someone in this forum once mentioned putting some type of code in for the colon and backslash instead such as creating a rule to look for "K|C3A|" or something like that, but all recommendations from that person failed. Does anyone know how I can create a rule to search for "K:\" (can be any drive letter....it's the colon and backslash that are important)? Thanks! Paul
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Current thread:
- How to detect drive letters accessed? Sheahan, Paul (PCLN-NW) (Jan 16)
- Re: How to detect drive letters accessed? Phil Wood (Jan 16)
- <Possible follow-ups>
- RE: How to detect drive letters accessed? Sheahan, Paul (PCLN-NW) (Jan 16)
- Re: How to detect drive letters accessed? Phil Wood (Jan 16)
- RE: How to detect drive letters accessed? David Hondel (Jan 17)
- Re: How to detect drive letters accessed? John Sage (Jan 17)
- RE: How to detect drive letters accessed? Sheahan, Paul (PCLN-NW) (Jan 17)