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

[Jamie Riden <jamie.riden () gmail com>]

As an aside, I think this (and similar sigs) should be extended to
cover the data: URI case, e.g.
pathToFiles=data://text/plain;base64,SSBsb3Z..

I've tested data: URIs as file include targets and they seem to work
ok if you have the appropriate allow_url_ setting.

cf: http://www.idontplaydarts.com/2011/03/php-remote-file-inclusion-command-shell-using-data-stream/

cheers,
 Jamie

On 25 January 2013 18:00, 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

-- 
Jamie Riden / jamie () honeynet org / jamie.riden () gmail com
http://uk.linkedin.com/in/jamieriden

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