Type packetstorm
Modified 2000-07-07T00:00:00


                                            `FSC Internet Corp. / SecureXpert Labs  
SecureXpert Labs Advisory [SX-20000620-3] - Partial Denial of  
Service in Check Point Firewall-1 on Windows NT  
The SMTP Security Server component of Check Point Firewall-1 4.0 and 4.1 is  
vulnerable to a simple network-based attack which raises the firewall load to  
Check Point Firewall-1 includes a component called the SMTP Security Server.  
This is an SMTP proxy, the use of which is required by several of Firewall-1's  
advanced SMTP email processing capabilities, including CVP-based virus  
scanning and URI filtering.  
The Check Point Firewall-1 SMTP Security Server in Firewall-1 4.0 and 4.1  
on Windows NT is vulnerable to a simple network-based attack which can increase  
the firewall's CPU utilization to 100%.  
Sending a stream of binary zeros over the network to the SMTP port on the firewall  
raises the target system's load to 100% while the load on the attacker's  
system machine remains relatively low. This can easily be reproduced from  
a Linux system using netcat with an input of /dev/zero, with a command such as  
"nc firewall 25 < /dev/zero".  
This vulnerability could allow a very quick and easy distributed attack  
on Check Point Firewall-1.  
Check Point Software Technologies has been informed of this vulnerability, and  
has assigned it incident ID# TT44913. As of June 20, 2000 Check Point  
has stated that a fix for this vulnerability will NOT be included in Service  
Pack 2 (SP-2) for Check Point firewall-1 4.1, but it will "probably be included  
in SP-3".  
Mike Murray, SecureXpert Labs  
Max Degtyar, SecureXpert Labs  
Richard Reiner, SecureXpert Labs  
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