McAfee > Theat Center > Virus Detail Page

Overview

This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.

Aliases

• Mistake

Characteristics

Typo Boot is a memory resident, Master Boot Record (MBR)/Boot Sector infecting virus. The Typo Boot virus is similar structurally to the Ping Pong virus, and may be a variant of Ping Pong.

Upon infection, Typo Boot becomes memory resident in upper memory.

Additional Comments:
The Typo Boot virus was first isolated in Israel by Y. Radai in June, 1989. This virus is a memory resident boot sector infector, taking up 2K at the upper end of system memory once it has installed itself memory resident. The major symptom that will be noticed on systems infected with the Typo Boot virus is that certain characters in printouts are always replaced with other phonetically similar characters. Since the virus also substitutes Hebrew letters for other Hebrew letters, the virus was most likely written by someone in Israel. Digits in numbers may also be transposed or replaced with other numbers. The substitutions impact printouts only, the screen display and data in files are not affected. The Typo Boot virus is similar structurally to the Ping Pong virus, and may be a variant of Ping Pong. It can be removed from a disk by using MDisk, CleanUp, DOS SYS command, or just about any Ping Pong disinfector.

Symptoms

The major symptom that on systems infected with the Typo Boot virus is that certain characters in printouts are always replaced with other phonetically similar characters. The virus also substitutes Hebrew letters for other Hebrew letters. Digits in numbers may also be transposed or replaced with other numbers. The substitutions impact printouts only, the screen display and data in files are not affected.

There is a 2K decrease in available system memory.

Method of Infection

The only way to infect a computer with an MBR/Boot Sector infector is to attempt to boot from an infected floppy diskette. The boot sector of the diskette has the code to determine if the diskette is bootable, and to display the "Non-system disk or disk error" message. It is this code that harbors the infection. By the time the non-system disk error message comes up, the infection has occurred. Once the virus is executed, it will infect the hard drive's MBR and may become memory resident. With every subsequent boot, the virus will be loaded into memory and will attempt to infect floppy diskettes accessed by the machine.

Removal

Windows 95/98:
Note for Windows 9x systems - during the boot process a Windows95 created boot disk will access the hard drive for information. Because of this an image of the virus may be in memory but not active.

To remove the virus, follow the following steps:
- If you use the McAfee emergency disk, hit F8 at the starting Windows 95 message, and select Step-by-step Configuration. Say yes to everything except processing the autoexec.bat file.
- At the a:, type
BOOTSCAN C: /BOOT /CLEAN /NOMEM

Windows NT/2000:
Shut down the PC and turn the power off. Obtain or create a virus free boot disk and scan disk. After booting, at the A:\ prompt, execute the following command:
BOOTSCAN C: /boot /clean

Once the virus has been removed, remove all floppy diskettes from the computer and reboot from the hard drive.

This will also clean an NTFS Master Boot Record and allow Windows NT to successfully reboot from the hard disk drive. VirusScan for DOS will not be able to read the rest of the NTFS partition. After starting Windows, execute VirusScan or NetShield to detect and clean Windows NT file infections which may exist.

Variants

Variants

N/A

All Information

Overview -

This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.

Aliases

• Mistake

Characteristics

Characteristics -

Typo Boot is a memory resident, Master Boot Record (MBR)/Boot Sector infecting virus. The Typo Boot virus is similar structurally to the Ping Pong virus, and may be a variant of Ping Pong.

Upon infection, Typo Boot becomes memory resident in upper memory.

Additional Comments:
The Typo Boot virus was first isolated in Israel by Y. Radai in June, 1989. This virus is a memory resident boot sector infector, taking up 2K at the upper end of system memory once it has installed itself memory resident. The major symptom that will be noticed on systems infected with the Typo Boot virus is that certain characters in printouts are always replaced with other phonetically similar characters. Since the virus also substitutes Hebrew letters for other Hebrew letters, the virus was most likely written by someone in Israel. Digits in numbers may also be transposed or replaced with other numbers. The substitutions impact printouts only, the screen display and data in files are not affected. The Typo Boot virus is similar structurally to the Ping Pong virus, and may be a variant of Ping Pong. It can be removed from a disk by using MDisk, CleanUp, DOS SYS command, or just about any Ping Pong disinfector.

Symptoms

Symptoms -

The major symptom that on systems infected with the Typo Boot virus is that certain characters in printouts are always replaced with other phonetically similar characters. The virus also substitutes Hebrew letters for other Hebrew letters. Digits in numbers may also be transposed or replaced with other numbers. The substitutions impact printouts only, the screen display and data in files are not affected.

There is a 2K decrease in available system memory.

Method of Infection

Method of Infection -

The only way to infect a computer with an MBR/Boot Sector infector is to attempt to boot from an infected floppy diskette. The boot sector of the diskette has the code to determine if the diskette is bootable, and to display the "Non-system disk or disk error" message. It is this code that harbors the infection. By the time the non-system disk error message comes up, the infection has occurred. Once the virus is executed, it will infect the hard drive's MBR and may become memory resident. With every subsequent boot, the virus will be loaded into memory and will attempt to infect floppy diskettes accessed by the machine.

Removal -

Removal -

Windows 95/98:
Note for Windows 9x systems - during the boot process a Windows95 created boot disk will access the hard drive for information. Because of this an image of the virus may be in memory but not active.

To remove the virus, follow the following steps:
- If you use the McAfee emergency disk, hit F8 at the starting Windows 95 message, and select Step-by-step Configuration. Say yes to everything except processing the autoexec.bat file.
- At the a:, type
BOOTSCAN C: /BOOT /CLEAN /NOMEM

Windows NT/2000:
Shut down the PC and turn the power off. Obtain or create a virus free boot disk and scan disk. After booting, at the A:\ prompt, execute the following command:
BOOTSCAN C: /boot /clean

Once the virus has been removed, remove all floppy diskettes from the computer and reboot from the hard drive.

This will also clean an NTFS Master Boot Record and allow Windows NT to successfully reboot from the hard disk drive. VirusScan for DOS will not be able to read the rest of the NTFS partition. After starting Windows, execute VirusScan or NetShield to detect and clean Windows NT file infections which may exist.

Variants

Variants -

N/A