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- Path: sparky!uunet!cs.utexas.edu!sun-barr!rutgers!netnews.upenn.edu!netnews.cc.lehigh.edu!news
- From: "a_rubin@dsg4.dse.beckman.com"@BIIVAX.DP.BECKMAN.COM
- Newsgroups: comp.virus
- Subject: Re: What is the best anti-virus program???
- Message-ID: <0017.9209031748.AA14082@barnabas.cert.org>
- Date: 31 Aug 92 19:51:37 GMT
- Sender: virus-l@lehigh.edu
- Lines: 107
- Approved: news@netnews.cc.lehigh.edu
-
- bleys@infopls.chi.il.us (Bleys Ahrens) writes:
-
- >All Anti-Virus programs are not created equal.
-
- >Most anti-virus packages on the market today (Norton, Central Point,
- >Untouchable, MacAffee) rely on pattern scanning as their primary method
- >of detecting a virus. In other words, they have a database of some sort
- >containing hundreds of strings or attributes that known viruses produce
- >when they infect a computer. This has worked relatively well in the
- >past, but unfortunately it is rapidly becoming unpractical. When new
- >viruses and strains are identified, the appropriate patterns must be
- >added to the databases of pattern scanning programs. This may be done
- >with updates to the program on disk, via download or manually typing
- >strings into the database.
-
- >The problem is that an average of three new viruses are being created
- >everyday. Add to this, the number of new mutating viruses which change
- >their appearance and method of operation as they spread and it quickly
- >becomes impossible to keep up with the spread of viruses. As more and
- >more users become interconnected though networks like the Internet,
- >Compuserve, Fidonet, etc. it becomes increasing easy to move a virus
- >from one side of the world to the other.
-
- >Another relatively new and dangerous sort of virus is the stealth
- >viruses. These viruses intercept calls from anti-virus programs as they
- >scan memory and disks. Boot sector stealth viruses generally make a copy
- >of the uninfected original areas and direct scanning programs to the
- >location of the copy, which appears to be normal. Stealth file viruses
- >on the other hand are often able to remove themselves from a file as it
- >is being scanned, so that the file appears clean. After the scan is
- >complete, the virus in memory then moves its code back into the infected
- >files.
-
- >Other recent threats to computer security include the publishing of a book
- >that tells how to write viruses and includes source code. (I would
- >prefer not to publicize it and intentionally left out the title.)
- >Another new threat is the recent posting on various BBSes of a some
- >programs that help people write mutating viruses.
-
- >In fairness to the makers of various anti-virus software manufacturers,
- >it must be pointed out that most programs on the market include methods
- >other than pattern scanning. Most also include TSR's which monitor for
- >suspicious disk and memory reads and writes. Some also include various
- >CRC checking methods which run some sort of algorithm on each file to
- >create a checksum which is then compared each time the file is executed.
- >A simple checksum works relatively well if you are absolutely sure that
- >your files aren't already infected. The problem is that some viruses
- >are smart enough to change the checksum values stored on the disk.
-
- >So what is the optimal solution... Well, I have been evaluating several
- >programs lately (Norton Anti-Virus, Central Point Anti-Virus, Fifth
- >Generation Untouchable, Certus Novi, Intel LanProtect, Brightworks
- >Development Sitelock and MacAffee Scan) and the one that seems have the
- >best potential to deal with the possibility of stealth and mutating
- >viruses is the relative newcomer, Novi from Certus.
-
- >This product does do some pattern scanning, but that is not the basic
- >paradigm used by this product. As I understand from my research, all
- >executable files have essentially the same type of header records. This
- >contains the basic information about the program and points to the
- >beginning of the code to run. What a virus will do is attach to the end
- >of the file and change the initial pointer to the start of the virus
- >code. At the end of the virus code is a pointer to the start of the
- >program code. Thus, the user runs the program, the virus executes and
- >most likely places itself into memory and then executes the program.
-
- >Novi works by checking the critical areas of the file (or disk boot records
- >for a boot sector scan) to see that everthing is the way it should be. If
- >pointers appear invalid or out of place, the product alerts the user to
- >a problem and then depending on the user response, can attempt to remove
- >the improper pointers and code. By not relying on pattern scanning, the
- >program will working with existing viruses as well as new mutations or
- >strains. I am still testing with it and others, but my opinion is that
- >this program offers the best protection into the future, without the
- >need of updates.
-
- >(This program has also rated very, very well in a variety of recent
- >magazine article and evaluations. It's file integrity checking is very
- >fast and is compatible with the major LAN OSes and with Windows.)
-
- >I suspect this article will provoke quite a few responses, and I hope
- >that some of the above anti-virus manufacturers with be available for
- >comments. I'm sure the folks from Certus can tell you a great deal more
- >about their product and would be more than happy to send you some
- >literature. (I'm not here to sell products for them, so I would prefer
- >not to answer a zillion questions about exactly how the product works.)
-
- >Bleys Ahrens
-
- >Disclaimer: I am not affiliated in any way with any of the above
- >mentioned products and/or companies. I am an IS professional with a
- >large international corporation. While the above evaluations occured
- >on company time, the opinions and views are strictly my own.
-
- >Comments generally welcomed. Direct flames to /dev/nul...
-
- >--
- >bleys@infopls.chi.il.us (Bleys Ahrens)
- >Infoplus BBS, +1 708 537 0247, v32bis. Home of Infoplus.
-
- Comments, anyone?
- - --
- Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea
- 216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal)
- My opinions are my own, and do not represent those of my employer.
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-