Snort mailing list archives

Re: false positive rules in snort 2.8.6.0


From: Will Metcalf <william.metcalf () gmail com>
Date: Fri, 4 Jun 2010 15:28:21 -0500

Ummmm so what is happening is that these rules are written to
fingerprint a protocol.  If I remember correctly dropping the traffic
identified by these sigs isn't enough to cripple e-mule.  Detection !=
Prevention...  Another example.. fire up a sniffer and and use a tcp
session splicing attack in InlineMode() against a target...  By the
time snort does reassembly the packets have already gone across the
wire.

Regards,

Will

On Fri, Jun 4, 2010 at 3:10 PM, Joel Esler <jesler () sourcefire com> wrote:
Okay, so you aren't saying they are falsing, you are saying that the rules
aren't dropping the traffic?

On Jun 4, 2010, at 4:00 PM, Lawrence R. Hughes, Sr. wrote:

Joel,

Thanks for the quick reply...

Although they are drop rules, the clients in both cases connect, allow
searches and downloads.

We do not use pcap, we thought that snort's coverage was enough.

Our main concern is about the RIAA...

Thanks,
Larry


----- Original Message -----
From: Joel Esler
To: Lawrence R. Hughes, Sr.
Sent: Friday, June 04, 2010 3:55 PM
Subject: Re: [Snort-users] false positive rules in snort 2.8.6.0
What are they falsing on?  Do you have a pcap?
J
On Jun 4, 2010, at 3:50 PM, Lawrence R. Hughes, Sr. wrote:

Hi All,

The following two (2) rules in p2p.rules are false positives... Be aware of
the RIAA

drop tcp $HOME_NET 4711 -> $EXTERNAL_NET any (msg:"P2P eDonkey server
response"
 flow:established,from_server; content:"Server|3A| eMule";
 fast_pattern:only; metadata:policy security-ips drop;
 reference:url,www.emule-project.net; classtype:policy-violation;
 sid:2587; rev:4;)
drop udp $HOME_NET any -> $EXTERNAL_NET 41170
(msg:"P2P Manolito Search Query"; flow:to_server; content:"|01 02 00 14|";
 depth:4; offset:16; metadata:policy security-ips drop;
 reference:url,openlito.sourceforge.net; reference:url,www.blubster.com;
 classtype:policy-violation; sid:3459; rev:5;)


Thanks,
Larry



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--
Joel Esler
302-223-5974
Jabber: jesler () sourcefire com


--
Joel Esler
302-223-5974
Jabber: jesler () sourcefire com

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