Virus Name: Annres
V Status: New
Discovery: January, 1996
Symptoms: .COM file growth; decrease in available free memory
Eff Length: 553 Bytes
Type Code: PRhCK - Parasitic Resident .COM Infector
Detection Method: ChAV, F-Prot, AVTK, IBMAV, ViruScan, PCScan,
Innoc, AVTK/N, IBMAV/N, NShld, NAV/N 2.0 9612+
Removal Instructions: Delete infected files
The Annres or Annres.553 virus was received in January, 1996,
along with two variants. There origin or point of isolation
is unknown. Annres is a memory resident infector of .COM files,
including COMMAND.COM. It does not infect very small .COM files.
When the first Annres infected program is executed, this virus
will install itself memory resident at the top of system memory
but below the 640K DOS boundary, not moving interrupt 12's
return. Available free memory, as indicated by the DOS CHKDSK
program from DOS 5.0, will have decreased by 1,168 bytes.
Interrupt 21 will be hooked by the virus in memory.
Once this virus is memory resident, it will infect .COM files
when they are executed. Infected files will have a file length
increase of 553 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 not be altered. The following text
string is encrypted within the viral code:
"Greetings to TRON, Sirius and MAN on the Moon!
It is unknown what this virus may do besides replicate.
Known variant(s) of Annres are:
Annres.1052: Received in January, 1996, this is an 1,052 byte
variant of the Annres virus described above. Its size in
memory is 2,160 bytes, hooking interrupt 21. It infects .COM
files when they are executed, adding 1,052 bytes to the file's
length. The virus will be located at the end of the file. The
program's date and time in the DOS disk directory listing will
not be altered. The following text string is encrypted within
the viral code:
"Greetings to TRON, Sirius and Man on the Moon!"
"THANX to Dark Angel and PS"
"Your harddisk has been infected with Mem-Annihilator II-*-
"Greetings to all virus writers elsewhere!"
Origin: Unknown January, 1996.