matt@psueclb.bitnet (10/05/88)
MDC SOFTWARE, INC. Is Proud to Announce the Integrity Shell: A New Breed Of Antiviral Software. The Integrity Shell is an MSDOS command interpreter or "shell" which provides more protection for its price than any other antiviral software. The shell is a natural, user-friendly environment which allows easy program development, yet provides an high degree of protection against computer viruses. All types of programs are protected (Batch files, COM and EXE files). In addition, protection is provided for programs that have never been run before (possible viruses or Trojan horses). The integrity shell dynamically maintains a list of all programs which are run. Modified, (possibly infected) or new programs (possible Trojan horses) are not run without confirmation. A high-speed cryptographic checksum verifies program integrity in a minimum amount of time. This checksum requires about the same amount of time as a highly optimized non- secure checksum or CRC, but is extremely difficult for a virus writer to "break" or forge. Operation and installation is simple. The shell is started from the DOS prompt, or from the 'AUTOEXEC.BAT' file. The program presents the MSDOS environment, with transparent checking embedded before program execution. No time penalty is paid during program execution. A supplied program creates a master list of the most frequently run programs, or the list can be built by the shell one program at a time. If a program has changed since it was last run, a query is given. For program development, simply answer 'y' to the prompt, and the new program information is saved (and the user is assured not re-testing an old version of a program). Answering 'n' to the prompt will cause the program to not be run. If no programs change and no new programs are run, operation of the shell is transparent aside from a slight delay in loading of programs due to the checking. The delay is approximately 1 second for an average program (17.5 Kilobytes). The main distinctions between this software and other antiviral software are: - The use of a cryptographic checksum. - The fact that it is a command interpreter, not a memory- resident (TSR) program. - The existence of a solid mathematical model of the protection. - Checking of the boot sector. - Checking COMMAND.COM before execution. - A unique self-test feature. It has been proven mathematically that this software protects against a large class of computer viruses and Trojan horses (Matt Cohen, "A New Integrity-Based Model For Limited Protection Against Computer Viruses", Master's Thesis, The Pennsylvania State University, 1988). The package includes the following programs: AVSH - The Integrity Shell. VIRUSCK - A screening program. CHECKALL - A program to check all protected programs. This program replaces a startup-checking system. ADDFILES - A program to add files to the protected list. PRICE: 29.95 MDC SOFTWARE Inc. Post Office Box 10589 State College, PA 16805-0589