Ada is a

computer virus A computer virus is a type of computer program that, when executed, replicates itself by modifying other computer programs and inserting its own code. If this replication succeeds, the affected areas are then said to be "infected" with a compu ...

that can affect any of the

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

operating systems. Ada was first discovered in 1991.

History

Ada virus was first discovered in Argentina in .

Characteristics

Ada is a memory resident virus that infects files. The Ada virus mainly targets .COM files, specifically COMMAND.COM and stays in the memory of the computer it infects after the program it infected executes. Infected programs have 2,600 bytes additional data inserted at the beginning of the file, and the file itself contains the text strings: * COMMAND.COM * PCCILLIN.COM * PCCILLIN.IMG * HATI-HATI !! ADA VIRUS DISINI !!Delete Another version of Ada has these text strings along with the strings BASURA BASURA repeated numerous times. Computers infected with the Ada virus often have a slow clicking sound emitting from their speakers; this clicking may sometimes change in pitch. Infected computers may show a "Disk Full" error even if the disk still has space on it. While infected with the Ada virus, system memory measured by the DOS

CHKDSK In computing, CHKDSK (short for "check disk") is a system tool and command in DOS, Digital Research FlexOS, IBM/ Toshiba 4690 OS, IBM OS/2, Microsoft Windows and related operating systems. It verifies the file system integrity of a volume ...

decreases by 21,296 bytes to 21,312 bytes. The virus resides in the memory after an infected file is run and will infect any other .COM files executed on the computer. It also hijacks interrupts 08, 13 and 21.

Infection route

There is only one way to infect a computer with the Ada virus; by executing an infected file. The infected file may come from a variety of sources: floppy disks, files downloaded from the Internet, and infected networks.

References

{{Reflist DOS file viruses