Virus Name: 4-days
V Status: New
Discovery: July, 1994
Symptoms: .COM & .EXE growth; file date/time changes;
decrease in total system & available free memory
Eff Length: 1,358 - 1,372 Bytes
Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector
Detection Method: F-Prot, IBMAV, AVTK, Sweep, ViruScan, NAV,
NAVDX, VAlert, PCScan,
AVTK/N, Sweep/N, IBMAV/N, NProt, NShld, NAV/N
Removal Instructions: Delete infected files
The 4-days virus was received in July, 1994. Its origin or point of
isolation is unknown. 4-days is a memory resident infector of .COM
and .EXE files, including COMMAND.COM.
When the first 4-days infected program is executed, the 4-days virus
will install itself memory resident at the top of system memory but
below the 640K DOS boundary, not moving interrupt 12's return. Total
system and available free memory, as indicated by the DOS CHKDSK
program, will have decreased by 1,360 bytes. Interrupt 21 will be
hooked by the virus in memory. Also at this time, the virus will
infect COMMAND.COM if it was not previously infected.
Once the 4-days virus is memory resident, it will infect .COM and
.EXE files when they are executed. Infected programs will have a
file length increase of 1,358 to 1,372 bytes with the virus being
located at the end of the file. The program's date and time in the
DOS disk directory listing will have been updated to the current
system date and time when infection occurred. The following text
strings are visible within the viral code in all infected files:
"COM EXE com exe OVL"
"ALIEN 1.0 written by P.K. on April 93 Good Luck !!!"