Editing Ada (computer virus)

{{Short description|Computer virus affecting DOS operating systems, discovered in 1991}}
{{other uses|Ada (disambiguation)}}
{{lead too short|date=September 2016}}
{{Infobox computer virus
 | Fullname                = ADA
 | Common name             = Ada
 | Technical name          = ADA
 | Family                  = N/A
 | Aliases                 = Ada, Ada-2600, Ada.2600
 | Classification          = [[Computer virus]]
 | Type                    = [[DOS]]
 | Subtype                 = [[COM file|COM]] infector. Random nuisance.
 | IsolationDate           = 1991
 | Isolation               = Unknown
 | Origin                  = [[Argentina]]
 | Author                  = Pessoa, nome,  feminino       = Ada ( Feliz, Própera, Desfragmentar, Vírus) Brasil
}}

'''Ada''' is a [[computer virus]] that can affect any of the [[DOS]] operating systems.<ref name="vil.nai.com">{{cite web |url=http://vil.nai.com/vil/content/v_98141.htm |title=ADA - Malware - McAfee Labs Threat Center |publisher=Vil.nai.com |accessdate=2014-04-10 |archive-url=https://web.archive.org/web/20090307004026/http://vil.nai.com/vil/content/v_98141.htm |archive-date=2009-03-07 |url-status=dead }}</ref> Ada was first discovered in 1991.

==History==
Ada virus was first discovered in Argentina in {{start date and age|1991|10|p=y}}.<ref>{{cite web|title=ADA|url=http://www.mcafee.com/threat-intelligence/malware/default.aspx?id=98141|publisher=McAfee|accessdate=12 February 2013}}</ref>

==Characteristics==
Ada is a [[memory resident]] virus<ref>{{Cite web|url=http://us.mcafee.com/VirusInfo/VIL/glossary_app.asp|title=McAfee &#124; Antivirus, VPN, Identity Protection - Download Free}}</ref> 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,<ref name="vil.nai.com"/> and the file itself contains the text strings:
* {{mono|COMMAND.COM}}
* {{mono|PCCILLIN.COM}}
* {{mono|PCCILLIN.IMG}}
* {{mono|HATI-HATI !! ADA VIRUS DISINI !!Delete}}

Another version of Ada has these text [[string (computer science)|strings]] along with the strings {{mono|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.<ref name="vil.nai.com" /> 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]] 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.<ref name="vil.nai.com"/>

==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.<ref name="vil.nai.com"/>

==References==
{{Reflist}}

[[Category:DOS file viruses]]