All Sys 9 Virus


 Virus Name:  All Sys 9 
 Aliases:     IOU 
 V Status:    Rare 
 Discovery:   September, 1992 
 Symptoms:    .COM & .EXE growth; TSR; "Abort, Retry, Ignore ?" error; 
              system reboots; unexpected beeps on system speaker 
 Origin:      Unknown 
 Eff Length:  1,838 - 2,088 Bytes 
 Type Code:   PRsAK - Parasitic Resident .COM & .EXE Infector 
 Detection Method:  ViruScan, F-Prot, IBMAV, AVTK, Sweep, 
                    NAV, NAVDX, VAlert, PCScan, ChAV, 
                    NShld, Sweep/N, NProt, AVTK/N, IBMAV/N, Innoc, NAV/N, 
                    LProt 
 Removal Instructions:  Delete infected files 
 
 General Comments: 
       The All Sys 9, or IOU, virus was submitted in September, 1992.  Its 
       origin or point of isolation is unknown.  All Sys 9 is a memory 
       resident infector of .COM and .EXE programs, including COMMAND.COM. 
 
       The first time a program infected with the All Sys 9 virus is 
       executed, this virus will install itself memory resident as a low 
       system memory TSR of 2,576 bytes.  It will have hooked interrupt 
       21. 
 
       Once memory resident, All Sys 9 will infect .COM and .EXE programs, 
       including COMMAND.COM, when they are executed.  Infected .COM 
       programs will have a file length increase of 1,838 to 1,863 bytes 
       with the virus being located at the beginning of the file. 
       Infected .EXE programs will have a file length increase of 2,080 
       to 2,088 bytes with the virus being located at the end of the 
       file.  .EXE programs may be reinfected by the virus, adding an 
       additional 2,080 bytes with each reinfection.  The file's date and 
       time in the DOS disk directory listing will not be altered.  The 
       following text strings can be found within the viral code in all 
       All Sys 9 infected programs: 
 
               "All System 9 - (c) 1991, Jerry C." 
               "Parity error at address 14344" 
               "Abort, Retry, Ignore ?" 
 
       Systems infected with All Sys 9 may experience the "Abort, Retry, 
       Ignore ?" message being displayed, after which pressing any key 
       on the system keyboard will result in a system reboot.  Beeping 
       will also occassionally be emitted from the system speaker. 

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