Re: Cisco PIX Security Notes

[Laurent LEVIER <llevier () ARGOSNET COM>]

Lisa,

I also many Pixes under my control. This "Firewall" does not log when it is scanned on its outside interface.
It is considering that someone is attempting access a already PATed session if the targetted port is already busy, and 
says nothing
if the port is not busy.

This is true from prom 4 to last. So using pix forbids to detect attacks on the device.

At 20:04 12/03/2001 -0800, Lisa Napier wrote:
> Hi Fabio,
>
> Thank you for your detailed analysis, although, we certainly would
> appreciate the opportunity to review this prior to public posting.  We
> prefer to minimize misinformation, as it can cause people to make decisions
> based on inaccurate information, which is never a good thing.
>
> We're currently in the process of reviewing your information and verifying
> these issues, but have a few initial comments.
>
> For the item listed as:
> -- Cisco PIX Firewall Logging Feature when firewall is probed.
>
> The PIX enforces that telnet to the outside interface must be IPsec
> protected.  The messages indicate that the packets are not IPsec protected
> and are therefore rejected.  This is documented in PIX configuration
> guide.  PIX generates *at most one* such syslog message per second.
>
> Additionally, for the item listed as:
>    --  Cisco PIX Firewall syn flood * EASY DOS WITH PIX
>
> This is a configuration mistake.  To activate TCP Intercept in the PIX, use
> a non-zero embryonic limit. The embryonic limit is not enabled in this
> configuration.  Additionally, the PIX TCP Intercept feature in the PIX is
> ported from the IOS Firewall version.  There should not be differences
> between the functionality of the two implementations.
>
> We are still in the process of analyzing your other statements.
>
> Thanks much,
>
> Lisa Napier
> Product Security Incident Response Team
> Cisco Systems
>
> At 07:32 PM 03/09/2001 +0100, Fabio Pietrosanti (naif) wrote:
> > Working with Cisco PIX Firewall i wrote some note about possible security
> > problem of Cisco PIX .
> >
> > Attached the paper Cisco_PIX_Notes.txt :)
> >
> >
> > --
> > Pietrosanti  Fabio          I.NET SpA, High Quality Access to the Internet
> > e-mail:  naif () inet it       ( Direzione Tecnica, Security Staff )
> >         firewall () inet it
> > PGP Key (DSS)               http://naif.itapac.net/naif.asc
> >
> > Home Page URL:            http://www.inet.it
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Laurent LEVIER
IT Systems & Networks, Unix System Engineer
Security Specialist

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