TOR Browser detection policy rule

[Lenny Hansson <lenny () netcowboy dk>]

To all SNORT users:

TOR Browser detection rule. Feel free to use.

I have tested the rule on 100GB data set no false positives so far. If
you find any false positives please let me know.

alert tcp $EXTERNAL_NET [9000:9300] -> $HOME_NET 1024: (msg:"NF - POLICY
- TOR browser starting up - TOR SSL NAT Check Detected - Typical TOR DNS
name"; flow:from_server,established;
pcre:"/www\.[a-z0-9]{12,21}\.(com|net)/i";
reference:url,networkforensic.dk; metadata:10122017;
classtype:policy-violation; sid:5021501; rev:3;)

It detects every time the TOR Browser is started.

Best Regards
Lenny Hansson
***********************************
E-mail: security () netcowboy dk
Key-ID: D282 E960 7B91 5A04 68DA AB33 4070 9EB8 9137 9877
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