tcp partial connections
Palumbo Mauro <[email protected]> Thu, 28 Nov 2019 15:02:38 +0000
| Newsgroups | gmane.comp.security.detection.bro |
|---|---|
| Message-ID | <[email protected]> |
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Hi everybody,
I have noticed that in many app level analyzers there is a sort of "safe=
ty check" in the method DeliverStream which essentially returns when the tc=
p session is partial, i.e.
if ( TCP() && TCP()->IsPartial() )
return;
This is true for example for the HTTP, SSH, SSL analyzers and more. My unde=
rstanding is that this is to prevent app layer analyzers or scripts relying=
on them from breaking down or missing some information when processing pac=
kets with possible missing bytes.
Am I right? How much reliable is this check TCP()->IsPartial() for partial=
tcp sessions in the tcp analyzer?
Thanks,
Mauro
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<p class=3D"MsoNormal"><span lang=3D"EN-US">Hi everybody,<o:p></o:p></span>=
</p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"> I have noticed tha=
t in many app level analyzers there is a sort of “safety check”=
in the method DeliverStream which essentially returns when the tcp session=
is partial, i.e.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"> &=
nbsp; if ( TCP() && TCP()->IsPartial() )<o:p></o:p></span>=
</p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"> &=
nbsp; return;<o:p></o=
:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">This is true for example for th=
e HTTP, SSH, SSL analyzers and more. My understanding is that this is to pr=
event app layer analyzers or scripts relying on them from breaking down or =
missing some information when processing
packets with possible missing bytes.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">Am I right? How much reliable i=
s this check TCP()->IsPartial() for partial tcp sessions in the tc=
p analyzer?<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">Thanks,<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">Mauro<o:p></o:p></span></p>
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