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

• Leprosy1.00

• NewsFlash

Characteristics

Leprosy is an overwriting, file infecting virus. It does not become memory resident. It infects .COM and .EXE files, including COMMAND.COM.

When you execute a file infected with the Leprosy virus, the virus overwrites the first 666 bytes of all .COM and .EXE files in the directory one level up from the current directory. If the current directory is the root directory, all files in the root directory are infected.

Additional Comments:
The Leprosy virus was discovered in the San Francisco Bay Area of California on August 1, 1990. This virus is a non-resident overwriting virus infecting .COM and .EXE files, including COMMAND.COM. Its original carrier file is suspected to be a file called 486COMP.ZIP which was uploaded to several BBSes. When you execute a program infected with the Leprosy virus, the virus will overwrite the first 666 bytes of all .COM and .EXE files in the directory one level up from the current directory. If the current directory is the root directory, all programs in the root directory will be infected. If COMMAND.COM is located in the directory being infected, it will also be overwritten. Infected files will show no file length increase unless they were originally less than 666 bytes in length, in which case their length will become 666 bytes. After the virus has infected the .COM and .EXE files, it will display a message. The message will be either: "Program to big to fit in memory" or: "NEWS FLASH!! Your system has been infected with the incurable decay of LEPROSY 1.00, a virus invented by PCM2 in June of 1990. Good luck!" The second message will only be displayed by one out of every seven .COM and .EXE files that the program infects. Since Leprosy is an overwriting virus, the programs which are infected with it will not function properly. In fact, once they are infected with this virus they will run for awhile (while the virus is infecting other files) and then display one of the two messages. The program execution will then end. If the system is booted from a diskette or hard drive that has Leprosy in its COMMAND.COM file, one of the above two messages will be displayed followed by: "Bad or missing Command Interpreter" This boot problem occurs because COMMAND.COM is no longer really COMMAND.COM. The boot will not proceed until a system boot diskette is inserted into the system and another boot is attempted. While Leprosy's messages are encrypted in the virus, infected files can be found by checking for the following hex string near the beginning of the file: 740AE8510046FE06F002EB08 Infected files must be deleted and replaced with clean, uninfected copies. There is no way to disinfect this virus since the first 666 bytes of the file have been overwritten, the virus does not store those bytes anywhere else. Known variant(s) of Leprosy are:

Symptoms

After the virus has infected a file, it displays a message. The message is either:

"Program to big to fit in memory"

or:

"NEWS FLASH!! Your system has been infected with the incurable decay of LEPROSY 1.00, a virus invented by PCM2 in June of 1990. Good luck!"

The second message is only displayed by one out of every seven .COM and .EXE files.

Since Leprosy is an overwriting virus, the files which are infected with it do not function properly. In fact, once they are infected with this virus they may run for awhile (while the virus is infecting other files) then display one of the two messages. The file execution then ends.

If the system is booted from a diskette or hard drive that has Leprosy in its COMMAND.COM file, one of the above two messages is displayed followed by:

"Bad or missing Command Interpreter"

This boot problem occurs because COMMAND.COM is no longer really COMMAND.COM. The user must reboot the system using a system boot diskette.

Infected files must be deleted and replaced with clean, uninfected copies. There is no way to disinfect this virus since the first 666 bytes of the file have been overwritten, the virus does not store those bytes anywhere else.

Infected files do not show a file length increase unless they were originally less than 666 bytes in length, in which case their length becomes 666 bytes.

Method of Infection

The only way to infect a computer with a file infecting virus is to execute an infected file on the computer. The infected file may come from a multitude of sources including: floppy diskettes, downloads through an online service, network, etc. Once the infected file is executed, the virus may activate.

Removal

All Users :
Script,Batch,Macro and non memory-resident:
Use current engine and DAT files for detection and removal.

PE,Trojan,Internet Worm and memory resident :
Use specified engine and DAT files for detection. To remove, boot to MS-DOS mode or use a boot diskette and use the command line scanner:

Additional Windows ME/XP removal considerations

Users should not trust file icons, particularly when receiving files from others via P2P clients, IRC, email or other mediums where users can share files.

AVERT Recommended Updates :

* Office2000 Updates

* Malformed Word Document Could Enable Macro to Run Automatically (Information/Patch )

* scriptlet.typelib/Eyedog vulnerability patch

* Outlook as an email attachment security update

* Exchange 5.5 post SP3 Information Store Patch 5.5.2652.42 - this patch corrects detection issues with GroupShield

For a list of attachments blocked by the Outlook patch and a general FAQ, visit this link .
Additionally, Network Administrators can configure this update using an available tool - visit this link for more information .

It is very common for macro viruses to disable options within Office applications for example in Word, the macro protection warning commonly is disabled. After cleaning macro viruses, ensure that your previously set options are again enabled.

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

• Leprosy1.00

• NewsFlash

Characteristics

Characteristics -

Leprosy is an overwriting, file infecting virus. It does not become memory resident. It infects .COM and .EXE files, including COMMAND.COM.

When you execute a file infected with the Leprosy virus, the virus overwrites the first 666 bytes of all .COM and .EXE files in the directory one level up from the current directory. If the current directory is the root directory, all files in the root directory are infected.

Additional Comments:
The Leprosy virus was discovered in the San Francisco Bay Area of California on August 1, 1990. This virus is a non-resident overwriting virus infecting .COM and .EXE files, including COMMAND.COM. Its original carrier file is suspected to be a file called 486COMP.ZIP which was uploaded to several BBSes. When you execute a program infected with the Leprosy virus, the virus will overwrite the first 666 bytes of all .COM and .EXE files in the directory one level up from the current directory. If the current directory is the root directory, all programs in the root directory will be infected. If COMMAND.COM is located in the directory being infected, it will also be overwritten. Infected files will show no file length increase unless they were originally less than 666 bytes in length, in which case their length will become 666 bytes. After the virus has infected the .COM and .EXE files, it will display a message. The message will be either: "Program to big to fit in memory" or: "NEWS FLASH!! Your system has been infected with the incurable decay of LEPROSY 1.00, a virus invented by PCM2 in June of 1990. Good luck!" The second message will only be displayed by one out of every seven .COM and .EXE files that the program infects. Since Leprosy is an overwriting virus, the programs which are infected with it will not function properly. In fact, once they are infected with this virus they will run for awhile (while the virus is infecting other files) and then display one of the two messages. The program execution will then end. If the system is booted from a diskette or hard drive that has Leprosy in its COMMAND.COM file, one of the above two messages will be displayed followed by: "Bad or missing Command Interpreter" This boot problem occurs because COMMAND.COM is no longer really COMMAND.COM. The boot will not proceed until a system boot diskette is inserted into the system and another boot is attempted. While Leprosy's messages are encrypted in the virus, infected files can be found by checking for the following hex string near the beginning of the file: 740AE8510046FE06F002EB08 Infected files must be deleted and replaced with clean, uninfected copies. There is no way to disinfect this virus since the first 666 bytes of the file have been overwritten, the virus does not store those bytes anywhere else. Known variant(s) of Leprosy are:

Symptoms

Symptoms -

After the virus has infected a file, it displays a message. The message is either:

"Program to big to fit in memory"

or:

"NEWS FLASH!! Your system has been infected with the incurable decay of LEPROSY 1.00, a virus invented by PCM2 in June of 1990. Good luck!"

The second message is only displayed by one out of every seven .COM and .EXE files.

Since Leprosy is an overwriting virus, the files which are infected with it do not function properly. In fact, once they are infected with this virus they may run for awhile (while the virus is infecting other files) then display one of the two messages. The file execution then ends.

If the system is booted from a diskette or hard drive that has Leprosy in its COMMAND.COM file, one of the above two messages is displayed followed by:

"Bad or missing Command Interpreter"

This boot problem occurs because COMMAND.COM is no longer really COMMAND.COM. The user must reboot the system using a system boot diskette.

Infected files must be deleted and replaced with clean, uninfected copies. There is no way to disinfect this virus since the first 666 bytes of the file have been overwritten, the virus does not store those bytes anywhere else.

Infected files do not show a file length increase unless they were originally less than 666 bytes in length, in which case their length becomes 666 bytes.

Method of Infection

Method of Infection -

The only way to infect a computer with a file infecting virus is to execute an infected file on the computer. The infected file may come from a multitude of sources including: floppy diskettes, downloads through an online service, network, etc. Once the infected file is executed, the virus may activate.

Removal -

Removal -

All Users :
Script,Batch,Macro and non memory-resident:
Use current engine and DAT files for detection and removal.

PE,Trojan,Internet Worm and memory resident :
Use specified engine and DAT files for detection. To remove, boot to MS-DOS mode or use a boot diskette and use the command line scanner:

Additional Windows ME/XP removal considerations

Users should not trust file icons, particularly when receiving files from others via P2P clients, IRC, email or other mediums where users can share files.

AVERT Recommended Updates :

* Office2000 Updates

* Malformed Word Document Could Enable Macro to Run Automatically (Information/Patch )

* scriptlet.typelib/Eyedog vulnerability patch

* Outlook as an email attachment security update

* Exchange 5.5 post SP3 Information Store Patch 5.5.2652.42 - this patch corrects detection issues with GroupShield

For a list of attachments blocked by the Outlook patch and a general FAQ, visit this link .
Additionally, Network Administrators can configure this update using an available tool - visit this link for more information .

It is very common for macro viruses to disable options within Office applications for example in Word, the macro protection warning commonly is disabled. After cleaning macro viruses, ensure that your previously set options are again enabled.

Variants

Variants -

N/A