RISKS-LIST: RISKS-FORUM Digest Monday, 30 November 1987 Volume 5 : Issue 67 FORUM ON RISKS TO THE PUBLIC IN COMPUTERS AND RELATED SYSTEMS ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator ******BE AWARE OF THE FOLLOWING IF YOU EXCHANGE DISKS WITH OTHER PEOPLE***** Date: Wed, 25 Nov 87 11:15 EDT From: Jeffrey James Bryan Carpenter Subject: Computer Virus To: risks@csl.sri.com From: IN%"MD4F@CMUCCVMA" "User Services List (ADVISE-L)" 23-NOV-1987 09:33 To: Jeff Carpenter <256521@vms.cis.pittsburgh.edu> Subj: Virus warning! Date: Mon, 23 Nov 87 08:05:57 EST From: "Kenneth R. van Wyk" <@vms.cis.pittsburgh.edu:LUKEN@LEHIIBM1.BITNET> Last week, some of our student consultants discovered a virus program that's been spreading rapidly throughout Lehigh University. I thought I'd take a few minutes and warn as many of you as possible about this program since it has the chance of spreading much farther than just our University. We have no idea where the virus started, but some users have told me that other universities have recently had similar probems. The virus: the virus itself is contained in the stack space of COMMAND.COM. When a pc is booted from an infected disk, all a user need do to spread the virus is to access another disk via TYPE, COPY, DIR, etc. If the other disk contains COMMAND.COM, the virus code is copied to the other disk. Then, a counter is incremented on the parent. When this counter reaches a value of 4, any and every disk in the PC is erased thoroughly. The boot tracks are nulled, as are the FAT tables, etc. All Norton's horses couldn't put it back together again... :-) This affects both floppy and hard disks. Meanwhile, the four children that were created go on to tell four friends, and then they tell four friends, and so on, and so on. Detection: while this virus appears to be very well written, the author did leave behind a couple footprints. First, the write date of the command.com changes. Second, if there's a write protect tab on an uninfected disk, you will get a WRITE PROTECT ERROR... So, boot up from a suspected virus'd disk and access a write protected disk - if an error comes up, then you're sure. Note that the length of command.com does not get altered. I urge anyone who comes in contact with publicly accessible (sp?) disks to periodically check their own disks. Also, exercise safe computing - always wear a write protect tab. :-) This is not a joke. A large percentage of our public site disks has been gonged by this virus in the last couple days. Kenneth R. van Wyk, User Services Senior Consultant, Lehigh University Computing Center (215)-758-4988