RUMORS OF WORMS AND TROJAN HORSES Danger Lurking in the Public Domain introduced and edited by Mike Guffey -INTRODUCTION There are literally thousands of free (or nearly free) programs available in computerdom's Public Domain. Those who use them save hundreds of dollars and thousands of hours. But many sneer at the idea of anything worthwhile being "free". Thus personal computing becomes divided into two camps: those who believe there are two camps and the rest who use Public Domain software (but sport no sense of moral superiority). For several years now rumors have circulated about dangerous programs which, when run, infest the innards of personal computers like parasites. And unlike most software, these insideous programs don't go away when the power is shut off. The story is they invade ROMs and "eat" memory away each time hardware is powered up. The legends have a basis in fact. For such horrors =do= exist in the world of mainframes. Probably first created by a bored or disgruntled programmer, such programs have been unleashed inside some of this country's largest computers. Generally, they are not outwardly visible, but begin the attack like a low grade fever. And these horrible little strings of code do damage a little at a time, slowly building in intensity. At first, things start going slightly awry. Ultimately, the system crashes or must be shut down. One recent magazine article called these creations "computer viruses". Just =how= damaging such programs can be (or have been) has not been fully publicized. But the facts lie on a razor's edge between science fiction and tomorrow's headlines. They are believed to pose a serious potential threat to national security. Some say the first of such monsters appeared on computer bulletin boards (BBS's) named "WORM.COM". [Remember that it is only recently that any online descriptions began to be posted next to program names. Some BBS's, notably CP/M based systems, still do not offer any explanation beyond the program name or notes in the associated message base part of the system.] And almost every computer user group has at least one experienced member who can tell the horrible tales of what these programs do. Actual witnesses to the destruction or victims of the atrocities seem to be =very= rare. Related to the twisted thinking behind such criminal mischief is the so-called "TWIT" phenomenon. Twits are computer vandals who glory in breaking into and "crashing" or seriously damaging remote computer systems. The targets range from neighborhood BBS's to any large computers which can be accessed via phone lines. And while such mental midgets have been glorified in the media and mis-labeled as "hackers", their very existence causes hysteria in and amongst the non-computing public at large. Computer security for large and small remote computer systems is getting better at screening out or scaring off "twits". But they still exist. There are indications that some have graduated from incessant attempts to break into BBS's. Instead they bring forth Trojan horses: damaging programs disguised as utilities and mis-labled or misdocumented as new treasures of the Public Domain. ==]#[=== The following data was recently retreived from a California BBS: WARNING! DANGEROUS PROGRAMS 1) Warning: Someone is [or may be] trying to destroy your data. Beware of a SUDDEN upsurge of [spurious] programs on Bulletin Boards and in the Public Domain. These programs purport to be useful utilities, but, in reality, are designed to sack your system. One has shown up as EGABTR, a program that claims to show you how to maximize the features of IBM'S Enhanced Graphics Adapter. It has also been spotted renamed as a new super-directory program. It actually erases the (F)ile (A)llocation (T)ables on your hard disk, [thereby rendering all data useless and inaccessible]. For good measure, it asks you to put a disk in Drive A:, then another in Drive B:. After it has erased those FATs too, it displays, " Got You! Arf! Arf! " Don't [casually] run any public-domain program that is not a known quantity. Have someone you know and trust vouch for it. ALWAYS examine it FIRST with DEBUG [or DDT or a similar utility]. Look at all the ASCII strings and data. If there is anything even slightly suspicious about it, [either] do a cursory disassembly [or discard it]. [For MSDOS programs] be wary of disk calls (INTERRUPT 13H), especially if the program has no business writing to the disk. Run your system in Floppy only mode with write protect tabs on the disk or junk disks in the drives. Speaking of Greeks bearing gifts, Aristotle said that the unexamined life is not worth living. The unexamined program [may not be] worth running. - from The Editors of PC July 23, 1985 Volume 4, Number 15 2) Making the rounds of the REMOTE BULLETIN BOARDS [is] a program called VDIR.COM. It is a little hard to tell what the program is suppose to do. What it actually does is TRASH your system. It writes garbage onto ANY disk it can find, including hard disks, and flashes up various messages telling you what it is doing. It's a TIME BOMB: once run, you can't be sure what will happen next because it doesn't always do anything immediately. At a later time, though, it can CRASH your system. Anyway, you'd do well to avoid VDIR.COM. I expect there are a couple of harmless, perhaps even useful, Public Domain programs floating about with the name VDIR; and, of course, anyone warped enough to launch this kind of trap once, can do it again. Be careful about untested "free" software. [paraphrased from Computing at Chaos Manor From the living Room By Jerry Pournelle BYTE Magazine, The small systems Journal] Two other examples of this type of program: 1. STAR.EXE presents a screen of stars then copies RBBS-PC.DEF and renames it. The caller then calls back later and d/l the innocently named file, and he then has the SYSOP'S and all the Users passwords. 2. SECRET.BAS This file was left on an RBBS with a message saying that the caller got the file from a mainframe, and could not get the file to run on his PC, and asked someone to try it out. When it was executed, it formatted all disks on the system. We must remember, that there are a few idiots out there who get great pleasure from destroying other peoples' equipment. Perverted I know, but we, the serious computer users, must take an active part in fighting against this type of stuff, to protect what we have. Be sure to spread this [message] to other BBS's across the country so that as many people as possible will be aware of what is going on. [from The Flint Board Flint, Mich (313) 736-8031] ===]#[=== -EPILOGUE Got your attention? There is no need to hatchet your modem and erase your communications software. While such programs can do tremendous damage, they are, fortunately, very rare. The following is an expansion of the countermeasures suggested above. A) More? Never, NEVER, N>E>V>E>R>! download and run Public Domain software (the first time) on a hard disk. While many programs are well known, it is a logical presumption that Trojan horse-type programs may have been uploaded with the name of a well-known utility. Or as a new version of one of your old favorites. Download them to a blank floppy or to a disk you have a current backup copy of. B) Get in the habit of examining unknown software with HEX/ASCII utilities that will reveal copyright data, documentation, program error and prompt messages. A good choice in MSDOS is called PATCH.COM and in CP/M there is DUMPX.COM. Even if a program is written in protected BASIC, you may still be able to find some useful data this way. [This is also a way to find documentation for good programs without .DOC files or descriptions.] C) Be wary of text files suggesting patches with DEBUG or DDT that you do not understand. ALWAYS make such modifications to a backup copy of your .COM, .EXE, .OVR files. There are no known examples of Trojan horses appearing this way, but... D) Make those BBS's which screen programs before making them available your first (but not your only) choice for acquiring new PD software. If you cannot figure out what a program does, =don't= upload it to some other BBS. E) Be wary but not paranoid. Be careful but not overcautious. Do not fan the fires of hysteria by More? passing along rumors of worms and Trojan horses. Speak of what you =know=. There are alot of good programs out there in the