









 | ber.
| Name | ber.
| | Aliases | onehalf, free love, dis, onehalf.madjid, onehalf.3518, onehalf.3544, onehalf.3577 and slovak bomber.
| | Discovered on | 1995 and it is in the wild |
Virus Information - ber.
:
This is a multipartite DOS virus that infects COM and EXE files under
DOS and partition table (MBR) of hard disks. The virus stays in memory
when the computer is booted from an infected disk. When the virus is active
in the memory, it will be infecting all the EXE and COM files opened or
executed in the floppy and network drives. It will not infect files
in the hard disk. The virus infects the partition table of the hard disk
the first time it infects the computer. The virus adds 3518, 3544 or 3577
bytes while infecting the file depending on the perticular variant of this
virus. One-half is a stealth virus so it tries to hide its presence. It
also tries not infect some anti-virus programs like SCAN, CLEAN, FINDVIRU,
GUARD, NOD, VSAFE and MSAV.
The virus contains the following text:
Dis is one half.
Press any key to continue ...
Did you leave the room ?
One-half virus encrypts the infected hard disk contents. Each time the
computer is booted the virus encrypts 2 cylinders of the hard disk from
the end. The last encrypted cylinder number and the encryption keys are
stored in the partition table of the had disk.When the virus is in memory,
it decrypts the data when it is accessed so the user will not notice the
encryption taking place. The encrypted data will be lost if the virus is
removed from the partition table without decrypting the data first. When
Protector Plus detects one-half, it decrypts the data first and then removes
the virus.

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