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- Information on the Brain Virus And Variants
- Prepared by David Stang
- National Computer Security Association
- Suite 309, 4401-A Connecticut Avenue NW
- Washington, DC 20008
- (202) 364-8252 (voice)
- (202) 364-1304 (BBS)
- This material (c) 1989 NCSA. It may not be reproduced
- without attribution to the NCSA.
-
- Synonyms: Pakistani Brain, Basit Virus.
-
- This virus originated in January, 1986, in Lahore
- Pakistan, but the first noticeable infection problems
- did not surface until 1988. In the spring of 1988, for
- instance, 100 machines at The Providence Journal-Bulletin
- were infected with it.
-
- The Brain is the only virus yet discovered that
- includes the valid names address and phone numbers of
- the original perpetrators. It was written by two
- brothers running a computer store in Lahore Pakistan.
- According to some sources, Basit Farooq Alvi, one of
- the brothers, wrote the virus so that it would infect
- machines running bootleg copies of a program he was
- selling for physicians. The original Brain put a
- copyright notice in the directory of floppy disks, but
- did no other damage.
-
- The Brain is a boot sector infector, approximately 3 K
- in length, that infects 5 1/4" floppies. It cannot
- infect hard disks. It will infect a diskette whenever
- the diskette is referenced. For example, a Directory
- command, executing a program from the diskette, copying
- a file from or to the diskette or any other access will
- cause the infection to occur. The virus stores the
- original boot sector, and six extension sectors,
- containing the main body of the virus, in available
- sectors which are then flagged as bad sectors.
- Diskettes have 3K of bad sectors (the normal numbers
- are none at all, or 5K, or sometimes more).
-
- No known intentional damage. Unintentional damage: it
- slows down diskette accesses and causes time-outs,
- which can make some diskette drives unusable.
-
- The virus is able to hide from detection by
- intercepting any interrupt that might interrogate the
- boot sector and re-directing the read to the original
- boot sector. Thus, programs like the Norton Utilities
- will be unable to see the virus.
-
- Infected diskettes are noticeable by "@BRAIN" or "(c)
- BRAIN" displayed in the volume label.
-
-
-
- Brain-B
-
- Synonyms: Brain-HD, the Hard Disk Brain, Houston Virus.
-
- This virus is identical in every respect to the
- original Brain, with the single exception that it can
- infect the C drive.
-
-
-
- Brain-C
-
- This virus is the Brain-B that has the volume label
- code removed. The volume label of infected diskettes
- does not change with this virus. This virus was
- difficult to detect since it does nothing overt in the
- system.
-
-
-
- Clone Virus
-
- This virus is the Brain-C that saves the original boot
- copyright label and restores it to the infected boot.
- The Basit & [A]mjad original Brain messages have been
- replaced with non-printable garbage that looks like
- instructions if viewed through Norton or other utility.
- Even if the system is booted from a clean diskette, it
- is virtually impossible to tell, by visual inspection,
- whether the hard disk is infected.
-
-
-
- Shoe_virus
-
- Synonym: UIUC Virus.
-
- This virus is the Brain-B virus that has been modified
- to include the message - "VIRUS_SHOE RECORD, v9.0.
- Dedicated to the dynamic memories of millions of virus
- who are no longer with us today". The message is never
- displayed.
-
- This might be identified with the Ashar vrus, as there
- is a VIRUS_SHOES RECORD v9.0 with the identifying
- string "ashar" at offset 04a6hex.
-
-
-
- Shoe_virus-B
-
- Experts disagree on the classification of this.
-
- @BULLET = It may be the Shoe_Virus that has been
- modified to so that it can no longer infect hard disks.
- The v9.0 has been changed to v9.1.
-
- @BULLET = There is a version of Brain with VIRUS_SHOE
- RECORD v9.0 which is incapable of activating a virus
- stored on hard disk due to the drive number being
- hardwired into the read routine for loading the virus.
- v9.1 may be the hard disk variant of Brain.
-
-
-
- Clone-B
-
- This is the Clone virus that has been modified to
- corrupt the FAT when it is booted after May 5, 1992.
- There are no other apparent modifications.
-
-
-
- Jork Virus
-
- This virus is the Shoe_virus with the identifying text
- at offset 0010hex reduced to "Welcome to the Dungeon
- (c) 1986 Brain", with the text at 0202hex reading "(c)
- 1986 Jork & Amjads (pvt) Ltd".
-
-
-
- Terse Shoe Virus
-
- This is a variant of the Shoe-virus with the initial
- text message truncated to a single line.
-
- end of text. Prepared 12/7/89