Snort mailing list archives

Re: Snort++ Escaping characters in signature content


From: Russ <rucombs () cisco com>
Date: Tue, 24 Jan 2017 12:03:04 -0500

Thanks - we will get that fixed.

On 1/24/17 10:54 AM, secres () linuxmail org wrote:
It was brought to my attention today that Snort++ seems to have a issue with escaping " characters in content rules. For instance, take the below signature that looks for ":\. If put through Snort++ 3.0.0-a4-222 you'll get a few errors. alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Testing Escape Characters"; content:"Look for \" and \; and \' and \\"; sid:11111; rev:1;)
o")~   Snort++ 3.0.0-a4-222
...
ERROR: /opt/snort3/etc/snort/error.rules:1 invalid byte code at 13
ERROR: /opt/snort3/etc/snort/error.rules:1 fast_pattern_offset must be less than the actual pattern length which is 0.
ERROR: /opt/snort3/etc/snort/error.rules:1 can't finalize content
But if you replace \" with byte code |22| it works just fine. I also tested this siganture in 2.9.8 and either one works. I typically don't have an issue with it because I always use |22| but since I've seen other signatures that use \" instead of the byte code is there a fix for this? alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Testing Escape Characters"; content:"Look for |22| and \; and \' and \\"; sid:11111; rev:1;)
o")~   Snort++ 3.0.0-a4-222
...
Snort successfully validated the configuration.
o")~   Snort exiting
        --== Initializing Snort ==--
...
Version 2.9.8.2 GRE (Build 335)
...
Snort successfully validated the configuration!
Snort exiting
Hope this helps anyone with the same issue.
Thanks!


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