Re: SiD:4129 - No FP - No FN but wrong

[Crusty Saint <saintcrusty () gmail com>]

Hi Joel,

I have rev:4 here, no updates are expected any time soon. For now there are
just two occurences. Given your reply i'll have a look at the pcap and if
still required forward you the data.

Thanks for your constructive reply


2011/3/28 Joel Esler <jesler () sourcefire com>

> What rev of the rule are you running?  The copy I have (4) has a content
> match, two byte jumps and a byte_test.  Plus there is a specific port coded
> into it.  That's fairly specific, but I see how a FP would occur.
>
> Do you have a pcap?
>
> Joel
>
> On Mar 28, 2011, at 11:08 AM, Crusty Saint wrote:
>
> Hi,
>
> For http://www.snort.org/search/sid/4129 "EXPLOIT Novell ZenWorks Remote
> Management Agent large login packet DoS attempt" i see no false-positive or
> false-negative reported but there possibly could be one now. Though the
> root-cause might well be PEBKAC.
>
> I think it is safe to assume such pebkac-positive would occur when a rule
> is active and applied on a network not using the specified service/protocol
> but i also hope snort's logic is sufficiently precise to eliminate such
> erronous detections.
>
> Based on what i've seen in the rule the detection is based on just two
> bytes so i assume the FP/FN rate to be much higher (? help ?) if used on a
> network without related traffic present.
>
>
> Best Regards,
>
> Saint Crusty
>
>
> --
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-- 
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Security Engineer - Tags: Analyst Systems Security Linux Firewall Network
Web Troubleshooting - If you think I deserve a rant, write me off-list

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