- Agena (computer virus)
Computer virus
Fullname = AGENA
Common name = Agena
Technical name = AGENA
Family = N/A
Aliases = Agena, Agena.723
Classification =Virus
Type =DOS
Subtype = COM andEXE infector. Replicant.
IsolationDate = 1992
Isolation = Unknown
Origin =Spain
Author = UnknownAGENA is a memory resident, file infecting
computer virus which infects .COM and .EXE files, includingcommand.com . It was discovered in Spain in September, 1992. Upon infection, Agena becomes memory resident at the top of system memory but below the 640KDOS boundary. Once it is memory resident, Agena infects .COM and .EXE files as they are executed. Infected programs will have a file length increase of 723 to 738byte s with the virus being located at the end of the file. An infected file's date and time in the DOS disk directory listing are not altered. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 1,296 bytes.Interrupt s 20 and 21 are hooked by the virus. It is unknown what Agena may do besides replicate. No text strings are visible within the viral code in infected programs.External links
* [http://www.probertencyclopaedia.com/L21.HTM Computer Viruses (A)] , by Probert Encyclopedia
* [http://vil.nai.com/vil/content/v_98146.htm Agena virus] , by McAfee
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