no need for multi-string IMO, string TCP is working fine with this type of scenario, have been tested many times

A.


On 8/19/2012 9:34 AM, Fawad Khan wrote:
I suggest to use multi string signature for this request or meta signature. I don't have acces to ips else I'll post the config.

On Saturday, August 18, 2012, Alexei Monastyrnyi wrote:

    Yeah, the reason I was asking for a config is that I could not
    understand what type if engine Bruno was using.

    Bruno,
    you should be fine with TCP string engine catching that line. TCP
    string engine would try to match it across several IP packets.
    This is the major difference between atomic engines and
    string-like engines. In atomic one the string you match has to be
    in a single IP packet.

    Now, things which I can see go wrong are:
    -  you are not using TCP string engine
    - your regex is lame
    - you are trying to match traffic gong in the wrong direction. You
    shoudl match in direction from attacker to victim.
    - accordingly TCP port should be 23 TO the service

    Len us know how you go.

    HTH
    A.

    On 8/19/2012 8:45 AM, Mike Rojas wrote:
    I think this one depends so much in how the command is placed,

    Mainly because you can do sh run, show running-config, sh runn,
    etc. Now, I have seen that some types of telnet clients, send
    character per character making it difficult to the IPS
    to catch the string.

    My advice here, get and IP logging, open it with wireshark, see
    how the string is being sent and then create the string tcp
    signature.

    Mike.

    ------------------------------------------------------------------------
    Date: Sun, 19 Aug 2012 08:16:20 +1000
    From: [email protected] <javascript:_e({}, 'cvml',
    '[email protected]');>
    To: [email protected] <javascript:_e({}, 'cvml',
    '[email protected]');>
    CC: [email protected] <javascript:_e({}, 'cvml',
    '[email protected]');>
    Subject: Re: [OSL | CCIE_Security] IPS Question

    could you post your signature config in text?

    On 8/18/2012 4:12 PM, Bruno Silva wrote:

        Hi Guys,

        I was studying some IPS functions and I came accross the regex session, 
which is no news to me but, I was wondering if I had the following cenario:

        R1 ------ IPS ------ASA1

        Suppose I want to reset a telnet connection from R1 to ASA1 when the user types 
show running-config how would I do that? I tried a lot of regular expressions but I 
wasn`t able to do it...Mainly because when the user is typping, it`s already sending the 
characters to the destination so if I do a common regular expression the session is not 
reseted or I can just sneak a way in to it doing stuff like typing show r and hitting 
"enter", comming back to the previous string and completing it, or even worst, 
I can type (space) show runn and it will still work. Can any of you guys think of a way 
of doing it?

        If it was another device I would do this with expect, because I would 
expect the prompt to change and then reset the connection, but I don`t think 
the Cisco IPS has this function does it?

        What do you guys think?

        Thank you very much,
        Bruno.
        _______________________________________________
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    _______________________________________________ For more
    information regarding industry leading CCIE Lab training, please
    visit www.ipexpert.com <http://www.ipexpert.com> Are you a CCNP
    or CCIE and looking for a job? Check out
    www.PlatinumPlacement.com <http://www.PlatinumPlacement.com>



--
FNK, CCIE Security#35578

_______________________________________________
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