This is a complex multipartite virus. Jackal infects COM and EXE files and the master boot sector on hard drives.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
When an infected file is executed, the virus modifies the partition table in the master boot sector and creates a new active partition where the virus resides. This means that you should not use the FDISK /MBR command to try to disinfect this virus. This also means that the hard drive partitions are not visible after a clean floppy boot.
When an infected machine is booted, the virus stays memory Resident, and infects COM and EXE files when they are accessed. Jackal tunnels DOS and BIOS interrupts to bypass virus monitors.
Jackal is also able to survive a warm reboot done by pressing Ctrl-Alt-Del. To boot clean you have to power down.
Jackal contains an activation routine, which overwrites part of the hard drive. This routine seems to be called by random.
Jackal gets its name from a string inside the virus body.
There are several variants known, 3101, 3118 and 3120 bytes in size.
McAfee Scan has had a false alarm of Jackal on hard drives with the OnTrack Disk Manager v6.03b software installed.
Description Created: Mikko Hypponen, F-Secure