Check Point FireWall-1 4.0和4.1版本存在漏洞。远程攻击者通过发送无效命令流（例如二进制0）到SMTP安全服务器代理导致拒绝服务。
These latest Service Packs address the described denial of service issue. It is important to note that even without the new service packs installed, this attack does not disable firewall operations in general, only operation of the SMTP Security Server, since the Security Server operates with a lower processor priority than the FireWall-1 kernel module. Check Point Software Firewall-1 4.0
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 (or other invalid SMTP commands) to the SMTP port on the firewall raises the target system's load to 100% while the load on the attacker's machine remains relatively low. According to Check Point Software this only disables mail relay while allowing other firewall operations to continue normally.
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".
FireWall-1 contains a flaw that may allow a remote denial of service. The issue is triggered when a remote attacker sends a string of binary data to port 25 of the firewall, and will result in loss of availability for the firewall.
Upgrade to version 4.0 SP7, 4.1 SP3 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.