Password guessing games with Check Point firewall
Security researchers have discovered two potentially serious flaws with Check Point's flagship FireWall-1 firewall which give rise to both username guessing and sniffing issues.
First, affected versions permit attackers to determine if a firewall username is valid without having to know the associated password. This enabling crackers to guess valid usernames using a dictionary attack.
The guessing rate is limited mostly by the firewall CPU rather than by the Internet link speed, according to security testing specialists NTA Monitor, which discovered the problem. In effect, this means that companies using a hi-spec firewall server increase the speed at which an attacker can guess passwords, NTA warns.
In addition, NTA Monitor discovered that VPN usernames are passed in the clear without encryption, allowing anyone who is able to sniff network traffic between VPN clients and the firewall to observe usernames in transit. The flaws exploit the Internet Key Exchange (IKE) encryption scheme and affect all Check Point FireWall-1 systems of 4.0 or above.
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- Vulnerability: Guessing or Sniffing SecuRemote Usernames Using IKE (4 September 2002)