F-HARE - Scanner and disinfector for the Hare viruses Copyright (c) 1996 Data Fellows Ltd OVERVIEW F-HARE will detect and disinfect the three known variants of the Hare virus (also known as HDEuthanasia and Krsna). This document gives a brief description of the Hare virus and explains how to use F-HARE to detect and disinfect this virus. ABOUT THE HARE VIRUS Hare is one of an increasing number of viruses distributed via the Internet, in the form of posts to Usenet News. On the 22nd of August and the 22nd of September, members of the Hare virus family will trigger, attempting to overwrite hard disks, floppy disks in drives A: and B:. Hare is a polymorphic, stealth, multi-partite virus. It is memory-resident and infects .COM and .EXE files, MBRs of hard disks, and floppy disk boot sectors. It is Windows 95 aware, enabling it to infect both files and the boot sectors of floppy disks used from Windows 95. Known variants are Hare.7610, Hare.7750 and Hare.7786 SYMPTOMS The symptoms of the Hare virus vary; under certain circumstances, it can render the fixed disk unbootable, or hide the DOS partitions if the system is booted from a clean system disk; it attempts to hide its changes to the length of infected files. Alternately, there may be no visible effect until the virus triggers. Since the symptoms can vary, it is recommended that suspect PCs be scanned using the F-HARE utility. HOW TO USE F-HARE: Run F-HARE with the drive letter of directory as a paramter. For example: F-HARE C: F-HARE Z:\USERS F-HARE will first check memory and will tell you if the Hare virus is in resident: "Scanning for Hare in memory - Infected!" If you find the Hare virus in memory, please reboot your computer from a clean write-protected system floppy diskette. This will ensure that the Hare virus is not in memory. Type F-HARE to determine if your Master Boot Record or any files are infected with the virus. If F-HARE finds the virus, you will be notified. Then, type F-HARE /disinf. F-HARE will disinfect your Master Boot Record and infected files. As detailed above, it is possible in some cases for the Hare virus to cause the DOS partition to be inaccessible when booted from a clean system disk. Do not worry, if this occurs, F-HARE can still remove the virus from both your hard disk and from any infected files. If F-HARE has found the HARE virus in your MBR, but you cannot see the DOS partition of your fixed disk after booting from a floppy disk, take the following steps to disinfect your machine fully: 1. Make sure you have booted from a clean write-protected system floppy diskette. 2. Type F-HARE c: /disinf F-HARE will remove the virus from the Master Boot Record. After the virus is removed from the Master Boot Record, you will see the message "virus removed" followed by the message "No hard disk found". 3. Simply reboot your computer again, from the clean write-protected floppy system diskette. You will now be able to see the C: drive. Once you can see it (by typing dir c:), type F-HARE c: /disinf to clean the virus from any files which may have become infected. WHAT ABOUT FLOPPIES? Since Hare can infect floppy diskettes, you will want to scan your floppy diskettes as well. To do this, invoke F-HARE using the /MULTI switch (eg F-HARE A: /MULTI). -- Virus analysis based on information from Mikko Hypponen, Data Fellows F-PROT Professional Support. F-HARE by Peter Szor, Data Fellows F-PROT Professional Development. Documentation by Sarah Gordon, Command Software F-PROT Professional Research and Development. F-HARE is protected by international copyright laws. F-HARE is (c) 1996 Data Fellows Ltd, and it is not in public domain or freeware, but you are free to use and share this software with no charges in non-commercial private use. Use of this software in other environments is not allowed in Europe, Asia and Africa without a license to F-PROT Professional or a current license from Frisk Software International. To purchase a license, contact your local distributor listed in PRO.DOC. Please redistribute F-HARE only with this documentation. You are not allowed to resell this software for your own profit (normal copying costs excluded) or claim to hold rights to this software. Although you may have the right to use F-HARE, it will remain the exclusive property of Data Fellows. Data Fellows does not warrant that the software is error free and we will not cover any costs created by function or malfunction of this program. Data Fellows also disclaims liability for possible consequential damages. If you cannot agree to these restrictions, you should not use F-HARE. Copyright (c) 1996 Data Fellows Ltd, Finland Data Fellows Ltd Paivantaite 8 FIN-02210 ESPOO FINLAND tel: +358-0-478 444 fax: +358-0-478 44 599 e-mail: F-PROT-Support@DataFellows.com www: http://www.DataFellows.com/