Re: my flow rule doesn't work

[Patrick Mullen <pmullen () sourcefire com>]

The "|17 03 03|" is never in a packet with the "|16 03 03|".  It looks like
they are message types, from opposite sides of the connection.  Since they
are in different packets, from different devices, they won't match a single
rule since they're never seen together.


Thanks,

~Patrick


On Thu, Sep 15, 2022 at 3:54 PM Xing Star via Snort-sigs <
snort-sigs () lists snort org> wrote:

> I make a rule to detect this pcap.But it seems not work at all.How can I
> do?
> Rule:
> alert tcp any any -> any any
> (msg:"TLS";flow:established,to_server;cotent:"|16 03 03|";content:"|14 03
> 03|";content:"|16 03 03|";content:"|17 03 03|";sid:87654321;rev:2;)
> I think it will work properly  ,but it can match to 14 03 03 16 03 03, it
> can't match 17 03 03 .
> And if the rule like this :alert tcp any any -> any any
> (msg:"TLS";flow:established,to_server;cotent:"|16 03 03|";content:"|14 03
> 03|";content:"|16 03 03|";content:"|16 03 03|";sid:87654321;rev:2;) , it
> can match from head.
> I don't know why . Should I need to modify config file?
> Please help me ,thanks very much
> [image: image.png]
> [image: image.png]
> [image: image.png]
>
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-- 
Patrick Mullen
Response Research Manager
Cisco TALOS

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