Abstract: A method and apparatus for detecting data modification in a layered operating system is disclosed. Outbound content indicators at different layers are compared to detect potential outbound data modifications. Likewise, inbound content indicators at different layers are compared to detect potential inbound data modifications. Content indicators include checksum, cryptographic hash, signature, and fingerprint indicators. Embodiments of the present invention enable detection of data modifications across an operating system's kernel and user mode spaces, prevention of modified outbound data from reaching a network, prevention of modified input data from reaching a user application, and detection of malware and faults within an operating system.

Abstract: A method and apparatus for detecting data modification in a layered operating system is disclosed. Outbound content indicators at different layers are compared to detect potential outbound data modifications. Likewise, inbound content indicators at different layers are compared to detect potential inbound data modifications. Content indicators include checksum, cryptographic hash, signature, and fingerprint indicators. Embodiments of the present invention enable detection of data modifications across an operating system's kernel and user mode spaces, prevention of modified outbound data from reaching a network, prevention of modified input data from reaching a user application, and detection of malware and faults within an operating system.

Abstract: A method and apparatus for detecting data modification in a layered operating system is disclosed. Outbound content indicators at different layers are compared to detect potential outbound data modifications. Likewise, inbound content indicators at different layers are compared to detect potential inbound data modifications. Content indicators include checksum, cryptographic hash, signature, and fingerprint indicators. Embodiments of the present invention enable detection of data modifications across an operating system's kernel and user mode spaces, prevention of modified outbound data from reaching a network, prevention of modified input data from reaching a user application, and detection of malware and faults within an operating system.

Abstract: A method and apparatus for detecting data modification in a layered operating system is disclosed. Outbound content indicators at different layers are compared to detect potential outbound data modifications. Likewise, inbound content indicators at different layers are compared to detect potential inbound data modifications. Content indicators include checksum, cryptographic hash, signature, and fingerprint indicators. Embodiments of the present invention enable detection of data modifications across an operating system's kernel and user mode spaces, prevention of modified outbound data from reaching a network, prevention of modified input data from reaching a user application, and detection of malware and faults within an operating system.

Abstract: The present invention relates to network security systems and, more particularly, to a method and apparatus for maintaining a TCP connection when the payload data of a TCP segment transmitted from source to destination is modified. The present invention allows the payload data of a TCP segment to be modified and, specifically, changed in length by an intermediate device during a TCP connection between any two hosts while adhering to the semantics of the TCP protocol so that the TCP connection may be maintained.

Abstract: A firewall system for protecting network elements of computer systems against attack from hosts on the Internet is described herein. The firewall system comprises a front-end server attached to the Internet and a back-end server attached to and between the computer systems to protect the front-end server. The front-end server is configured to prevent all unrequested packets from directly reaching the back-end server and the computer systems attached thereto. The back-end server is configured to forward to the Internet any request originating form the computer systems and to gather signed packets stacked at the front-end server level.