RE: Do ICMP re-directs actually work ?

["Ofir Arkin" <ofir () sys-security com>]

Naveed,

Try to look for the registry setting in Windows 2000 that is IGNORING
redirects. This might be your problem.

BTW - I would suggest you use a tool called 'sing' it is a better
implementation of icmpush by the same coder - alfredo andreas omella.

Hope this helps

Ofir Arkin [ofir () sys-security com]
Founder
The Sys-Security Group
http://www.sys-security.com
PGP CC2C BE53 12C6 C9F2 87B1 B8C6 0DFA CF2D D360 43FA


-----Original Message-----
From: Naveed Anwar [mailto:naveed () middleoffice com] 
Sent: ג 30 אוקטובר 2001 4:56
To: pen-test () securityfocus com
Cc: ofir () sys-security com
Subject: Do ICMP re-directs actually work ?


Hi All

I have just been conducting a test in one of our labs by sending ICMP
redirects to a Windows 2000 Advanced Server using ICMPUSH. Using a
sniffer I see the packet successfully leave my machine, then again
from the target box I see the re-direct arrive. Say for example my
target machine is called Pepsi, and I tell it to redirect any packets
for a machine called Fanta to a dead gateway, hence communication to
Fanta will fail for the lifetime of the redirect.

Now my understanding is that the target server (Pepsi) should now
have updated its local routing table with respect to the Fanta
machine. Then from Pepsi I try to ping/telnet/http/ftp etc..(i.e
establish communication) to Fanta I am able to. The point is since I
told Pepsi via a redirect to send all traffic for Fanta to a
blackhole, how is the communication working.

One interesting point is that when I issue a netstat -rn to view the
routing table, I see no route update from the ICMP redirect. 

After reading Ofir's excellent paper I understand most ICMP
implementations are OS specific, therefore I guess redirects do not
work in Win2000 or Linux 6.2 which I also tested..or am I doing
something horribly wrong?

Thanks
Naveed


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