Stack-based buffer overflow in Check Point VPN-1 Server 4.1 through 4.1 SP6 and Check Point SecuRemote/SecureClient 4.1 through 4.1 build 4200 allows remote attackers to execute arbitrary code via an ISAKMP packet with a large Certificate Request packet.

The design of the Internet Key Exchange (IKE) protocol, when using Aggressive Mode for shared secret authentication, does not encrypt initiator or responder identities during negotiation, which may allow remote attackers to determine valid usernames by (1) monitoring responses before the password is supplied or (2) sniffing, as originally reported for FireWall-1 SecuRemote.

Check Point FireWall-1 SecuRemote/SecuClient 4.0 and 4.1 allows clients to bypass the "authentication timeout" by modifying the to_expire or expire values in the client's users.C configuration file.

Check Point VPN-1 4.1SP4 using SecuRemote returns different error messages for valid and invalid users, with prompts that vary depending on the authentication method being used, which makes it easier for remote attackers to conduct brute force attacks.

Nokia Firewall Appliances running IPSO 3.3 and VPN-1/FireWall-1 4.1 Service Pack 3, IPSO 3.4 and VPN-1/FireWall-1 4.1 Service Pack 4, and IPSO 3.4 or IPSO 3.4.1 and VPN-1/FireWall-1 4.1 Service Pack 5, when SYN Defender is configured in Active Gateway mode, does not properly rewrite the third packet of a TCP three-way handshake to use the NAT IP address, which allows remote attackers to gain sensitive information.

Format string vulnerability in Check Point VPN-1/FireWall-1 4.1 allows a remote authenticated firewall administrator to execute arbitrary code via format strings in the control connection.