[comp.virus] Disk write loses 10 characters --- a virus?

stephenc@cunixf.cc.columbia.edu (Stephen Chung) (10/01/90)

Hi, NetLanders,

I have recently been asked to look at an Epson Equity (PC compatible)
which is behaving strangely when writing to the hard disk.  All the
files are read fine, but I discovered that whenever I try to write any
file onto the hard disk, the first 10 bytes of the data to be written
are lost.  EXACTLY 10 bytes.  Every time.  I then tried to boot the
machine with a write-protected DOS disk and the problem went away.
However, as soon as I tried to run a copy of PFS:Write from a diskette,
the problem appeared again.  Any pointers?

Thanks.

CHESS@YKTVMV.BITNET (David.M.Chess) (10/05/90)

stephenc@cunixf.cc.columbia.edu (Stephen Chung) asks if file writes
mysteriously losing the first 10 characters might be a virus.  It
certainly might!  The 9800:0000 virus (aka 1559) does that; I seem to
recall it does it whenever the month is Sept-Dec, although it might be
Oct-Dec.  Any good virus scanner should be able to find the infected
files for you, if that is indeed your problem.  Also just look for
files that are larger than they ought to be; it adds about 1559 bytes
to both COM and EXE files.  DC