Re: IPS packet reject handling doesn't work as expected

[Joel Esler <jesler () sourcefire com>]

Can you send both pcaps?

--
Joel Esler
Sent from my iPad 

On Jan 25, 2013, at 1:00 PM, Lukas Matt <lukas.matt () sophos com> wrote:

> Hello @all,
>
> I have following setup:
>
> DNAT rule to make an internal webserver reachable by using the external IP address.
> command from client to server:
> curl -v -s 'http://[hostname]/rss.php?pathToFiles=https&apos;
>
> triggered rule:
> 2931/finished_pullpork_rules/plain.rules:alert tcp $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (msg:"SERVER-WEBAPP 
> miniBB rss.php pathToFiles remote file include attempt"; flow:to_server,established; content:"rss.php"; nocase; 
> http_uri; content:"pathToFiles="; nocase; http_uri; pcre:"/pathToFiles=(ftp|https?)/Ui"; metadata:policy security-ips 
> drop, service http; reference:url,osvdb.org/show/osvdb/51460; classtype:web-application-attack; sid:18479; rev:7;) 
> So from my view the incoming GET request from my IP should be rejected (or maybe dropped).
> But in the tcpdump I can see that this GET request routed to the internal webserver.
>
> It worked fine after I removed the perl regex from the rule and the content-modifier http_uri.
>
> What exactly  could be wrong with the regex/modifier?
>
> Regards,
> Lukas Matt
>
>
> -- 
> Lukas Matt | lukas.matt () sophos com | Deep Packet Inspection Researcher
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