Virus Encyclopedia
Welcome to the Virus Encyclopedia of Panda Security.
Jerusalem.B | |
Threat Level Damage Distribution |
At a glance
 |
| Common name: | Jerusalem.B |
| Technical name: | Jerusalem B Family |
| Threat level: | Low |
| Alias: | Viernes 13 |
| Type: | Virus |
| Effects: | It activates on Friday 13th and deletes all the files that are run. |
| Affected platforms: | MS-DOS |
| Detection updated on: | Jan. 1, 1991 |
| Statistics | No |
| Country of origin: | ISRAEL |
Brief Description | |
| Jerusalem.B is a resident virus that infects files with an EXE, SYS and COMextension. This virus is activated when the date on the system clock is Friday 13th and it deletes all files run on the computer. Jerusalem.B increases the size of infected files. The size of a file increases every time the infected file is run. It can also cause the computer to slow down. Jerusalem.B does not use any specific means to spread. It can reach computers through the usual means used by viruses: Internet downloads, floppy disks, FTP, etc. |
Visible Symptoms | |
Jerusalem.B is difficult to identify, as it does not display any messages or warnings that indicate that it has infected a computer. |
Tech details
Effects |
Jerusalem.B has the following effects on the affected computer: - It activates when the system date is Friday 13th and it deletes all the files run on the computer.
- It infects files with a COM, EXE or SYS extension. The size of these files increase. For example, the size of COM files increase by 1813 bytes.
- It reduces the memory available in the computer.
- The size of EXE or SYS files increases by between 1808 and 18922 bytes.
- It causes the computer to slow down.
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Infection strategy
In order to carry out the infection, Jerusalem.B goes memory and resident reroutes the interrupts 21h and 08h.
Jerusalem.B increases the size of the files it infects many times. To be more precise, it increases the size of a file with an EXE, COM or SYS extension every time it is run.
Means of transmission
Jerusalem.B does not use any specific means to spread. It can reach computers through the usual means of transmission used by viruses: floppy disks, CD-ROMs, e-mail messages with infected attachments, Internet downloads, FTP, etc.
Further Details
There are many versions of Jerusalem.B, which include the following: Anarkia, Antivirus, Apocalypse, Bogota, Captain, Trips, etc.
