ftp.pasteur.org/FAQ/

home *** CD-ROM | disk | FTP | other *** search

/ ftp.pasteur.org/FAQ/ / ftp-pasteur-org-FAQ.zip / FAQ / computer-virus / alt-faq / part1 next >

Wrap

Internet Message Format | 2000-03-24 | 32.0 KB

Path: senator-bedfellow.mit.edu!dreaderd!not-for-mail Message-ID: <computer-virus/alt-faq/part1_953842042@rtfm.mit.edu> Supersedes: <computer-virus/alt-faq/part1_952514862@rtfm.mit.edu> Expires: 21 Apr 2000 20:07:22 GMT X-Last-Updated: 2000/02/29 Organization: none From: George Wenzel <gwenzel@telusplanet.net> Newsgroups: alt.comp.virus,comp.virus,alt.answers,comp.answers,news.answers Followup-To: alt.comp.virus Subject: [alt.comp.virus] FAQ Part 1/4 Approved: news-answers-request@MIT.EDU X-no-archive: yes Originator: faqserv@penguin-lust.MIT.EDU Date: 23 Mar 2000 20:09:03 GMT Lines: 702 NNTP-Posting-Host: penguin-lust.mit.edu X-Trace: dreaderd 953842143 2960 18.181.0.29 Xref: senator-bedfellow.mit.edu alt.comp.virus:101518 comp.virus:30976 alt.answers:47996 comp.answers:40195 news.answers:180074 Archive-name: computer-virus/alt-faq/part1 Posting-Frequency: Fortnightly URL: http://www.sherpasoft.org.uk/acvFAQ/ Maintainer: Co-maintained by David Harley, Bruce Burrell, and George Wenzel -----BEGIN PGP SIGNED MESSAGE----- alt.comp.virus (Frequently Asked Questions) ******************************************* Version 1.1 : Part 1 of 4 Last modified 19th August 1999 ("`-''-/").___..--''"`-._ `6_ 6 ) `-. ( ).`-.__.`) (_Y_.)' ._ ) `._ `. ``-..-' _..`--'_..-_/ /--'_.' ,' (il),-'' (li),' ((!.-' ADMINISTRIVIA ============= New or modified entries are flagged with two plus symbols at the beginning of the line or paragraph. Maintenance of this FAQ is now shared between the following: David Harley <D.Harley@icrf.icnet.uk> George Wenzel <gwenzel@telusplanet.net> Bruce Burrell <bpb@umich.edu> Suggestions, corrections, new material etc. may be sent to any of us, but will normally require the approval of all co-maintainers. Material which can be used with a minimum of editing is particularly welcome. Sometimes we are told that something should be in here which already is. Please check carefully. Suggestions for material which - - -isn't- already in is welcomed, but we're there's no guarantee as to if and when we'll write new material. If you give us a draft, it makes things much easier (and obviously you'll be credited). The <Viruses and the Macintosh> FAQ is now co-maintained by David Harley and Susan Lesch, and the authoritative version is the one at http://www.macvirus.com/. Disclaimer - - ---------- This document is primarily concerned with defending the integrity of computing systems and preventing damage caused by viruses or other malicious and/or other unauthorized software. It attempts to address many of the issues which are frequently discussed on alt.comp.virus, but does not claim to represent all shades of opinion among the users of a.c.v. - in particular, it does not include information which, in our estimation, is likely to be of more help to those interested in the spreading of unauthorized and/or malicious software than to those who wish to be protected from it. Nor is it claimed to be up-to-date in all respects. This document is an honest attempt to help individuals with computer virus-related problems and queries. It can *not* be regarded as being in any sense authoritative, and has no legal standing. The authors accept no responsibility for errors or omissions, or for any ill effects resulting from the use of any information contained in this document. Not all the views expressed in this document are those of the maintainers, and those views which *are* those of the maintainers are not necessarily shared by their respective employers. Copyright Notice - - ---------------- Copyright on all contributions to this FAQ remains with the authors and all rights are reserved. It may, however, be freely distributed and quoted - accurately, and with due credit. It may not be reproduced for profit or distributed in part or as a whole with any product or service for which a charge is made, except with the prior permission of the copyright holders. To obtain such permission, please contact one of the co-maintainers of the FAQ. Such permission will normally be forthcoming as long as (1) reproduced text is quoted accurately (2) it is made clear that such text is derived from the FAQ (3) it is made clear that the latest version of the FAQ is available from the newsgroup and from the official home of the FAQ on the world-wide web, which is currently <http://www.sherpasoft.org.uk/acvFAQ/> (4) the e-mail addresses of all co-maintainers of the FAQ are included as a contact point. The FAQ is also available at: http://www.faqs.org/faqs/computer-virus/alt-faq/ - - ---------------------------------------------------------------------- PREFACE ======= (i) What is the FAQ, and whom is it for? ----------------------------------- This FAQ is intended to make available answers to questions which are repeatedly asked on alt.comp.virus, and tries to gather the most useful information regarding this group and the issues discussed here into a relatively short document. The intention is to provide an easily-digested document for newcomers, as a means of saving those who regularly reply to posted questions having to re-invent the wheel each time. We recommend that you read this FAQ in conjunction with the comp.virus (VIRUS-L)FAQ, which gives more detailed information regarding some issues which are, inevitably, covered in both FAQs. The VIRUS-L/comp.virus FAQ is regularly posted to the comp.virus newsgroup. The latest version should be available at: http://www.faqs.org/faqs/computer-virus/faq/index.html ftp://ftp.datafellows.com/pub/misc/anti-vir/vlfaq200.zip A very terse mini-FAQ maintained by George Wenzel is posted regularly to alt.comp.virus weekly and also available at: http://www.faqs.org/faqs/computer-virus/mini-faq/ (ii) Credits/Acknowledgements ------------------------ The following have contributed text and/or ideas and/or proofreading/corrections and/or URLs to the a.c.v. FAQ. Vesselin Bontchev, Dennis Boon, Bruce Burrell, Graham Cluley, Henri Delger, Edward Fenton, Nicola Ferri, Sarah Gordon, David Harley, R. Wallace Hale, Norman Hirsch, Matthew Holtz, Jan Hruska, Mikko H. Hypponen, Douglas A. Kaufman, Tom Kelchner, Paul Kerrigan, Chengi (Jimmy) Kuo, Susan Lesch, Gerard Mannig, Martin Overton, Mike Ramey, Perry Rovers, Tom Simondi, Megan Skinner, Fridrik Skulason, Robert Slade, Alan Solomon, Ken Stieers, Hector Ugalde, George Wenzel, Caroline Wilson, and Tarkan Yetiser. [Apologies to anyone who's fallen off the list.] Acknowledgement is also due to the work of Ken Van Wyk, former moderator of VIRUS-L/comp.virus, and the contributors to the comp.virus FAQ. Thanks also to ked@intac.com (aka Phreex), who mailed me a copy of the FAQ he posted to a.c.v. some months before this one was begun, David J. Loundy for assistance regarding legal issues, and to Nick FitzGerald, the moderator of comp.virus and maintainer of the comp.virus FAQ. (iii) Guide to posting etiquette -------------------------- Messages asking for help posted to alt.comp.virus are more likely to receive a useful response if they conform to accepted standards of civility. The newsgroup news.announce.newusers includes information on good newsgroup etiquette, or try ftp://rtfm.mit.edu/pub/usenet/news.announce.newusers/ http://www.fau.edu/rinaldi/netiquette.html However, adhering to the following guidelines would be particularly helpful: * Keep your lines short (say 72 characters per line), so that anyone who follows up doesn't have to reformat quoted text to keep it readable). * Don't quote all or most of a message you're following up unless it's either very short, or necessary in order to address each point made. In the latter case, please put the point you're answering close to your answer and try to format it so that it's readable. Remember that some people have to pay for connection/download time. * On the other hand, a message which says something like 'I totally agree' without including enough of the original for us to tell what you're agreeing with is a waste of bandwidth. * Keep it polite. It's unlikely that anyone who replies to your posting is being paid to do so, and it wouldn't excuse bad manners if they were. Of course, the cut and thrust of debate may be a different matter altogether.... * Asking for a reply by direct e-mail may be reasonable if you need an urgent solution or are using a borrowed account. It isn't reasonable if you simply can't be bothered to check newsgroups. At least try to think up a good excuse, and be prepared to offer a summary to the group. * Check that there isn't already a thread on the subject you're asking about before posting yet another 'Has anyone heard of the GOOD TIMES virus?' message. If there is, check it first: the answer to your question may already be there (if it isn't in this document!). Please remember that many people have to pay for connect time, and don't appreciate duplicate postings or uuencoded binaries. * If you want to follow up a message which doesn't seem particularly relevant to alt.comp.virus, check the 'Newsgroups:' header: there have been a lot of responses to spammings recently which have made increased the bandwidth used, often quite unnecessarily. * Please don't post test messages here unless you really need to: use one of the newsgroups intended for the purpose: there is probably one local to your news server - ask your Systems Administrator, provider or local helpdesk. If you must post to the entire Internet, use misc.test - if you do, put the word IGNORE in your Subject: field, or you'll get auto-responder messages in your mail for weeks afterwards. Look through the postings in news.announce.newusers for relevant guidelines before you post. * If you get into an exchange of E-mail, please remember that not everyone can handle all forms of E-mail attachment (uuencoded, MIME format etc. - if it's text, *send* it as text. NB also that (uu)encoding text makes it longer as well as unreadable, so don't! * Don't assume that everyone uses or should use HTML-savvy mailers. There are good reasons why some people don't. * If you stick to what can be read easily on an 80 x 24 text window, -everyone- can read it. (iv) How to ask on the alt.comp.virus newsgroup for help --------------------------------------------------- The more relevant information you give us, the more we can help you. It helps to tell us the following: * What you think the problem is (you might think it's a virus, but maybe it isn't) * What the symptoms are. If you ran some software that gave you a message, tell us which package, version number, and the exact wording of the message. * Please be as accurate as possible about the order in which events happened. * If just one file is infected, give the filename. * If you're running more than one anti-virus product, please list them (including version number), and say what each one said about the possible virus. * Which version of which operating system you are running. * Any other configuration information which you think may have a bearing. Don't take action, then ask if that was the right action - if it wasn't, it's too late. Don't just ask "I've got xyz virus, can anyone help me". - - ------------------------------------------------------------------------- Table of Contents ***************** Part 1 ------ (1) I have a virus - what do I do? (2) Minimal glossary (3) What is a virus (Trojan, Worm)? (4) How do viruses work? (5) How do viruses spread? (6) How can I avoid infection? (7) How does antivirus software work? Part 2 ------ (8) What's the best anti-virus software (and where do I get it)? (9) Where can I get further information? (10) Does anyone know about * Mac viruses? * UNIX viruses? * macro viruses? * the AOLGold virus? * the PKZip300 trojan virus? * the xyz PC virus? * the Psychic Neon Buddha Jesus virus? * the blem wit virus * The Irina Virus * Ghost * General Info on Hoaxes/Erroneous Alerts (11) Is it true that...? (12) Favourite myths * DOS file attributes protect executable files from infection * I'm safe from viruses because I don't use bulletin boards/shareware/Public Domain software * FDISK /MBR fixes boot sector viruses * Write-protecting suspect floppies stops infection * The write-protect tab always stops a disk write * I can infect my system by running DIR on an infected disk Part 3 ------ (13) What are the legal implications of computer viruses? Part 4 ------ (14) Miscellaneous Are there anti-virus packages which check zipped/archived files? What's the genb/genp virus? Where do I get VCL and an assembler, & what's the password? Send me a virus. It said in a review...... Is it viruses, virii or what? Where is alt.comp.virus archived? What about firewalls? Viruses on CD-ROM. Removing viruses. Can't viruses sometimes be useful? Do I have a virus, and how do I know? What should be on a (clean) boot disk? How do I know I have a clean boot disk? What other tools might I need? What are rescue disks? Are there CMOS viruses? How do I know I'm FTP-ing 'good' software? What is 386SPART.PAR? Can I get a virus to test my antivirus package with? When I do DIR | MORE I see a couple of files with funny names... Reasons NOT to use FDISK /MBR Why do people write/distribute viruses? Where can I get an anti-virus policy? Are there virus damage statistics? What is ICSA approval? What language should I write a virus in? No, seriously, what language are they written in? [DRD], Doren Rosenthal, the Universe and Everything What are CARO and EICAR? - - ------------------------------------------------------------------------- (1) I have a virus problem - what do I do? ========================================== The following guidelines will, one hopes, be of assistance. However, you may get better use out of them if you read the rest of this document before acting rashly... If you think you may have a virus infection, *stay calm*. Once detected, a virus will rarely cause (further) damage, but a panic action might. Bear in mind that not every one who thinks s/he has a virus actually does (and a well-documented, treatable virus might be preferable to some problems!). Reformatting your hard disk is almost certainly unnecessary and very probably won't kill the virus. If you've been told you have something exotic, consider the possibility of a false alarm and check with a different package. If you have a good antivirus package, use it. Better still, use more than one. If there's a problem with the package, use the publisher's tech support and/or try an alternative package. If you don't have a package, get one (see section on sources below). If you're using Microsoft's package (MSAV) get something less out-of-date. Follow the guidelines below as far as is practicable and applicable to your situation. Try to get expert help *before* you do anything else. If the problem is in your office rather than at home there may be someone whose job includes responsibility for dealing with virus incidents. Follow the guidelines below as far as is practicable and applicable. * Do not attempt to continue to work with an infected system, or let other people do so. * Generally, it's considered preferable to switch an infected system off until a competent person can deal with it: don't allow other people to use it in the meantime. If possible, close down applications, Windows etc. properly and allow any caches/buffers to flush, rather than just hit the power switch. * If you have the means of checking other office machines for infection, you should do so and take appropriate steps if an infection is found. * If you are unable to check other machines, assume that all machines are infected and take all possible steps to avoid spreading infection any further. * If there are still uninfected systems in the locality, don't use floppy disks on them [except known clean write-protected DOS boot floppies] * users of infected machines should not *under any circumstances * trade disks with others until their systems and disks are cleaned. * if the infected system is connected to a Novell network, Appleshare etc., it should be logged off all remote machines unless someone knowledgeable says different. If you're not sure how to do this, contact whoever is responsible for the administration of the network. You should in any case ensure that the network administrator or other responsible and knowledgeable individual is fully aware of the situation. * No files should be exchanged between machines by any other means until it's established that this can be done safely. * Ensure that all people in your office and anyone else at risk are aware of the situation. * Get *all* floppy disks together for checking and check every one. This includes write-protected floppies and program master disks. Check all backups too (on tape or file servers as well as on floppy). (2) Minimal Glossary ==================== [There is room for improvement and expansion here. Contributions will be gratefully accepted.] * AV - AntiVirus. Sometimes applied as a shorthand term for anti-virus researchers/programmers/publishers - may include those whose work is not AV research, but includes virus-control. (See also Vx.) * BSI - Boot Sector Infector (= BSV - Boot Sector Virus) * BIOS - Basic Input Output System * CMOS - Memory used to store hardware configuration information * DBR - DOS Boot Record * DBS - DOS Boot Sector * False Positive - When an antivirus program incorrectly reports a virus in memory or infecting a file or system area. Heuristic scanners & integrity checkers are, by definition, somewhat more prone to these. Also known as false alarms, though this may have a wider application. * False Negative - Essentially, a virus undetected by an antivirus program. * In-the-wild - describes viruses known to be spreading uncontrolled to real-life systems, as opposed to those which exist only in controlled situations such as anti-virus research labs. Virus code which has been published but not actually found spreading out of control is not usually regarded as being in-the-wild. * MBR - Master Boot Record (Partition Sector) * TSR - A memory-resident DOS program, i.e one which remains in memory while other programs are running. A good TSR should at least detect all known in-the-wild viruses and a good percentage of other known viruses. Generally, TSRs are not so good with polymorphic viruses, and should not be relied on exclusively. Most TSR scanners don't detect macro viruses. * vx - Those who study, exchange and write viruses, not necessarily with malicious intentions So we're frequently told here... * VxD - A Windows program which can run in the background. A scanner implemented as a VxD has nearly all the advantages of a DOS TSR, but can have additional advantages: for instance, a good VxD will scan continuously *and* for all the viruses detected by an on-demand scanner. * Zoo - suite of viruses used for testing. See the comp.virus FAQ for fuller definitions of some of these terms and others which aren't addressed here. (3) What is a virus (and what are Trojans and Worms)? ===================================================== A (computer) virus is a program (a block of executable code) which attaches itself to, overwrites or otherwise replaces another program in order to reproduce itself without the knowledge of the PC user. Most viruses are comparatively harmless, and may be present for years with no noticeable effect: some, however, may cause random damage to data files (sometimes insidiously, over a long period) or attempt to destroy files and disks. Others cause unintended damage. Even benign viruses (apparently non-destructive viruses) cause significant damage by occupying disk space and/or main memory, by using up CPU processing time, and by the time and expense wasted in detecting and removing them. A Trojan Horse is a program intended to perform some covert and usually malicious act which the victim did not expect or want. It differs from a destructive virus in that it doesn't reproduce, (though this distinction is by no means universally accepted). A dropper is a program which installs a virus or Trojan, often covertly. A worm is a program which spreads (usually) over network connections. Unlike a virus, it does not attach itself to a host program. In practice, worms are not normally associated with personal computer systems. There is an excellent and considerably longer definition in the Mk. 2 version of the Virus-L FAQ. (The following is a slightly academic diversion) A lot of bandwidth is spent on precise definitions of some of the terms above. I have Fridrik Skulason's permission to include the following definition of a virus, which I like because it demonstrates most of the relevant issues. #1 A virus is a program that is able to replicate - that is, create (possibly modified) copies of itself. #2 The replication is intentional, not just a side-effect. #3 At least some of the replicants are also viruses, by this definition. #4 A virus has to attach itself to a host, in the sense that execution of the host implies execution of the virus. -- #1 is the main definition, which distinguishes between viruses and Trojans and other non-replicating malware. #2 is necessary to exclude for example a disk-copying program copying a disk, which contains a copy of itself. #3 is necessary to exclude "intended" not-quite-viruses. #4 is necessary to exclude "worms", but at the same time it has to be broad enough to include companion viruses and .DOC viruses. (4) How do viruses work? ======================== A file virus attaches itself to a file (but see the section below or the comp.virus FAQ on the subject of companion viruses), usually an executable application (e.g. a word processing program or a DOS program). In general, file viruses don't infect data files. However, data files can contain embedded executable code such as macros, which may be used by virus or trojan writers. Recent versions of Microsoft Word are particularly vulnerable to this kind of threat. Text files such as batch files, postscript files, and source code which contain commands that can be compiled or interpreted by another program are potential targets for malware (malicious software), though such malware is not at present common. Boot sector viruses alter the program that is in the first sector (boot sector) of every DOS-formatted disk. Generally, a boot sector infector executes its own code (which usually infects the boot sector or partition sector of the hard disk), then continues the PC bootup (start-up) process. In most cases, all write-enabled floppies used on that PC from then on will become infected. Multipartite viruses have some of the features of both the above types of virus. Typically, when an infected *file* is executed, it infects the hard disk boot sector or partition sector, and thus infects subsequent floppies used or formatted on the target system. Macro viruses typically infect global settings files such as Word templates so that subsequently edited documents are contaminated with the infective macros. The following virus types are more fully defined in the comp.virus FAQs (see preamble): * STEALTH VIRUSES - viruses that go to some length to conceal their presence from programs which might notice. * POLYMORPHIC VIRUSES - viruses that cannot be detected by searching for a simple, single sequence of bytes in a possibly-infected file, since they change with every replication. * COMPANION VIRUSES - viruses that spread via a file which runs instead of the file the user intended to run, and then runs the original file. For instance, the file MYAPP.EXE might be 'infected' by creating a file called MYAPP.COM. Because of the way DOS works, when the user types MYAPP at the C> prompt, MYAPP.COM is run instead of MYAPP.EXE. MYAPP.COM runs its infective routine, then quietly executes MYAPP.EXE. N.B. this is not the *only* type of companion (or 'spawning') virus. * ARMOURED VIRUSES - viruses that are specifically written to make it difficult for an antivirus researcher to find out how they work and what they do. (5) How do viruses spread? ========================== A PC is infected with a boot sector virus (or partition sector virus) if it is (re-)booted (usually by accident) from an infected floppy disk in drive A. Boot Sector/MBR infectors are the most commonly found viruses, and cannot normally spread across a network. These (normally) spread by accident via floppy disks which may come from virtually any source: unsolicited demonstration disks, brand-new software (even from reputable sources), disks used on your PC by salesmen or engineers, new hardware, or repaired hardware. A file virus infects other files when the program to which it is attached is run, and so *can* spread across a network (often very quickly). They may be spread from the same sources as boot sector viruses, but also from sources such as Internet FTP sites and bulletin boards. (This applies also to Trojan Horses.) A multipartite virus infects boot sectors *and* files. Often, an infected file is used to infect the boot sector: thus, this is one case where a boot sector infector could spread across a network. (6) How can I avoid infection? ============================== There is no way to guarantee that you will avoid infection. However, the potential damage can be minimized by taking the following precautions: * make sure you have a clean boot disk - test with whatever (up-to-date!) antivirus software you can get hold of and make sure it is (and stays) write-protected. Boot from it and make a couple of copies. * use reputable, up-to-date and properly-installed anti-virus software regularly. (See below) If you use a shareware package for which payment and/or registration is required, do it. Not only does it encourage the writer and make you feel virtuous, it means you can legitimately ask for technical support in a crisis. * do some reading (see below). If you're a home user, you may well get an infection sooner or later. If you're a business user, it'll be sooner. Either way you'll benefit from a little background. If you're a business user you (or your enterprise) need a policy. * don't rely *solely* on newsgroups like this to get you out of trouble: it may be a while before you get a response (especially from a moderated group like comp.virus), and the first response you act upon may not offer the most appropriate advice for your particular problem. * if you use a shareware/freeware package, make sure you have hard copy of the documentation *before* your system falls apart! * always run a memory-resident scanner to monitor disk access and executable files before they're run. * if you run Windows, a reputable anti-virus package which includes DOS *and* Windows components is likely to offer better protection than a DOS only package. If you run Windows 95, you need a proper Win95 32-bit package for full protection. * make sure your home system is protected, as well as your work PC. * check all new systems and all floppy disks when they're brought in (from *any* source) with a good virus-scanning program. * acquire software from reputable sources: 2nd-hand software is frequently unchecked and sometimes infected. Bear in mind that shrinkwrapped software isn't necessarily unused. In any case, reputable firms have shipped viruses unknowingly. * once formatted, keep floppies write-disabled except when you need to write a file to them: then write-disable them again. * make sure your data is backed up regularly and that the procedures for restoring archived data *work* properly. * scan pre-formatted diskettes before use. * Get to know all the components of the package you're using and consider which bits to use and how best to use them. Different packages have different strengths: diversifying and mixing and matching can, if carefully and properly done, be a good antivirus strategy, especially in a corporate environment * if your PC can be prevented with a CMOS setting from booting with a disk in drive A, do it (and re-enable floppy booting temporarily when you need to clean-boot). CMOS settings - - ------------- Some CMOSes come with special anti-virus settings. These are normally vague about what they do but typically they write-protect your hard disk's boot sector and partition sector (MBR). This can be some use against boot sector viruses but may false alarm when you upgrade your operating system. One sensible setting to make (if your CMOS allows) is to adjust the boot sequence of your PC. Changing the default boot-up drive order from A: C: to C: will mean that the PC will attempt to boot from drive C: even if a floppy disk has been left in drive A:. This way boot sector virus infection can often be avoided. Remember, however, to set your CMOS back temporarily if you ever *do* want to boot clean from floppy (for example, when running a cryptographical checksummer after a cold boot). SCSI controllers have their own BIOS. On some systems, this will override the boot sequence set in CMOS. It's always a good idea to check with a (known clean) bootable floppy after you've disabled floppy booting that it really is disabled. I don't think it's necessary to use the Rosenthal Simulator to do this, thank you, Doren. (7) How does antivirus software work? - - ------------------------------------- * Scanner (conventional scanner, command-line scanner, on-demand scanner) - a program that looks for known viruses by checking for recognisable patterns ('scan strings', 'search strings', 'signatures' [a term best avoided for its ambiguity]). * TSR scanner - a TSR (memory-resident program) that checks for viruses while other programs are running. It may have some of the characteristics of a monitor and/or behaviour blocker. * VxD scanner - a scanner that works under Windows or perhaps under Win 95, or both), which checks for viruses continuously while you work. * Heuristic scanners - scanners that inspect executable files for code using operations that might denote an unknown virus. * Monitor/Behaviour Blocker - a TSR that monitors programs while they are running for behaviour which might denote a virus. * Change Detectors/Checksummers/Integrity Checkers - programs that keep a database of the characteristics of all executable files on a system and check for changes which might signify an attack by an unknown virus. * Cryptographic Checksummers use an encryption algorithm to lessen the risk of being fooled by a virus which targets that particular checksummer. - - --------------------------------------------------------------------- End of a.c.v. FAQ Part 1 of 4 -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com> Comment: PGP Key ID 0xDCC35C75 available on Keyservers iQCVAwUBOLvlLLcpzG7cw1x1AQFOagQApMdBjccOExlbB42DTM5WCPeeK3SB1pqf KwbK3pok3c+8aolZpxr5TsIteVdMoJ2ATjOP13/SK02DPigUHzw7kn69C35ZDOh7 6n1F5RTzVLKXUB8wedU78ZAWS5hh/JY/EyM7718vAHT6kpgviaNK7MvxXxatPwDB LUiW7ziicS8= =WgMU -----END PGP SIGNATURE-----