Virus Profile: Jerusalem

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Virus Profile information details
Risk Assessment: Home Low | Corporate Low
Date Discovered: 10/1/1987
Date Added: 10/15/1987
Origin: Italy
Length: 1,808-1,822 Bytes
Type: Virus
Subtype: File Infector
DAT Required: 4002
Removal Instructions
   
 
 
   

Description

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.

Indication of Infection

Infected .COM files increase in size by 1,813 bytes. The virus is located at the beginning of the infected file. .EXE files increase in size by 1,808 to 1,822 bytes. The virus is located at the end of the infected file. Each reinfection adds an additional 1,808 bytes to the .EXE file. Jerusalem infected files have no change to their date and time in the DOS disk directory.

This virus redirects interrupt 8, and 1/2 hour after execution of the first infected file the system slows down by a factor of 10.

Additionally, some Jerusalem virus variants have a "black window" or "black box" appear on the lower left side of the screen which scrolls up the screen as the screen scrolls.

The Jerusalem virus activates after it becomes memory resident on Friday the 13th. At that time, it deletes any file the user attempts to execute.

The identifier for most Jerusalem strains is "sUMsDos", however, this identifier may not be found in the newer variants of Jerusalem.

Methods 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.

Aliases

1808(EXE), 1813(COM), ArabStar, BlackBox, BlackWindow, Friday13th, HebrewUniversity, Israeli, PLO, Russian
   

Virus Characteristics

Jerusalem is a memory resident, file infecting virus. Jerusalem infects .COM, .EXE, .SYS, .BIN, .PIF, and .OVL files. Jerusalem does not infect COMMAND.COM. The Jerusalem virus is thought to have been based on the Suriv 3.00 virus, though the Suriv 3.00 virus was isolated after the Jerusalem virus. The Jerusalem virus has been altered many times, and many other viruses have been based on its code. The description below is for a standard Jerusalem virus.

Upon infection, the Jerusalem virus becomes memory resident as a low system memory Terminate-and-Stay Resident (TSR) of 1,792 bytes. Interrupts 08 and 21 are hooked by the Jerusalem virus in memory.

Once the Jerusalem virus is memory resident, it infects files other than COMMAND.COM as they are executed. The Jerusalem virus may reinfect .EXE files due to a bug in the viral code.

Additional Comments:
The Jerusalem virus was originally isolated at Hebrew University in Israel in the Fall of 1987. As of November, 1991, it is thought to have now originated in Italy. Jerusalem is a memory resident generic file infector. Jerusalem viruses will infect .COM, .EXE, .SYS, .BIN, .PIF, and overlay files when they are executed .EXE files may be reinfected by the virus each time they are executed due to a bug in the viral code. The Jerusalem virus has been altered many times, and many other viruses have been based on its code. The description below is for a standard Jerusalem virus which reinfects .EXE files when they are executed. Other variants, or members of this family, are indicated below. The first time a program infected with the Jerusalem virus is executed, the Jerusalem virus will install itself memory resident as a low system memory TSR of 1,792 bytes. Interrupts 08 and 21 will be hooked by the Jerusalem virus in memory. Once the Jerusalem virus is memory resident, it will infect programs other than COMMAND.COM when they are executed. .COM programs will increase in size by 1,813 bytes with the virus being located at the beginning of the infected file. .EXE programs will increase in size by 1,808 to 1,822 bytes with the virus being located at the end of the infected file. Later, infected .EXE programs will be reinfected by the virus when they are again executed. Each reinfection will add an additional 1,808 bytes to the file. Jerusalem infected programs will have no change to their date and time in the DOS disk directory. This virus redirects interrupt 8, and 1/2 hour after execution of the first infected program the system will slow down by a factor of 10. Additionally, some Jerusalem virus variants will have a "black window" or "black box" appear on the lower left side of the screen which will scroll up the screen as the screen scrolls. The Jerusalem virus activates after it becomes memory resident on Friday the 13ths. At that time, it will delete any program the user attempts to execute. The identifier for most Jerusalem strains is "sUMsDos", however, this identifier may not be found in the newer variants of Jerusalem. The Jerusalem virus is thought to have been based on the Suriv 3.00 virus, though the Suriv 3.00 virus was isolated after the Jerusalem virus. Known members(s) of the Jerusalem Family are:

   
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:

SCANPM /ADL /CLEAN /ALL

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.

   

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