Aussie Dir

Upon infection, this virus becomes memory resident at the top of system memory but below the 640K DOS boundary. It hooks interrupt 21. Interrupt 12's return is not moved.

Once the Aussie Dir virus is memory resident, it infects two .COM files in the current directory whenever a DOS DIR command is executed.

Additional Comments:
The Aussie Dir, or Sdir, virus was submitted from Australia in March, 1993. It was discovered in Melbourne, Australia in January, 1993. Aussie Dir was originally submitted with the virus named "Sdir", but this name was not used as it is the name of a computer program unconnected to this virus. Aussie Dir is a memory resident infector of .COM programs, including COMMAND.COM. When the first Aussie Dir infected program is executed, this virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, hooking interrupt 21. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 608 bytes. Interrupt 12's return will not be moved. Once the Aussie Dir virus is memory resident, it will infect two .COM programs in the current directory whenever a DOS DIR command is executed. Infected programs will have a file length increase of 550 bytes with the virus being located at the end of the file. The program'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 Aussie Dir infected programs: "1 Did David Gerrold have a harley when he was one?" "2 Is John Brunner a shocking wave rider?" "3 Is William Gibson a neurotic romantic?" "4 Is Australian Parasite the Best?" "1:No, 2:Yes, 3: Probably, 4: Absolutley" "AP*.COM" The text string "AP" can also be found starting in the fourth byte of all infected files, this is the infection marker for the virus. Aussie Dir also contains destructive code to overwrite the current drive on the 29th day of a specific month, though due to a bug in the virus, this code will not be executed.

"1 Did David Gerrold have a harley when he was one?"
"2 Is John Brunner a shocking wave rider?"
"3 Is William Gibson a neurotic romantic?"
"4 Is Australian Parasite the Best?"
"1:No, 2:Yes, 3: Probably, 4: Absolutley"
"AP*.COM"

The text string "AP" is found starting in the fourth byte of all infected files. Aussie Dir also contains destructive code to overwrite the current drive on the 29th day of a specific month, though due to a bug in the virus, this code does not execute.

Total system and available free memory decreases by 608 bytes. Infected files have a file length increase of 550 bytes. The virus is located at the end of the file. The file's date and time in the DOS disk directory listing are not altered.

The only way to infect a computer with a file infecting virus is to execute an infected file on the computer. The infected file may come from a multitude of sources including: floppy diskettes, downloads through an online service, network, etc. Once the infected file is executed, the virus may activate.

All Users :
Script,Batch,Macro and non memory-resident:
Use current engine and DAT files for detection and removal.

PE,Trojan,Internet Worm and memory resident :
Use specified engine and DAT files for detection. To remove, boot to MS-DOS mode or use a boot diskette and use the command line scanner:

Additional Windows ME/XP removal considerations

Users should not trust file icons, particularly when receiving files from others via P2P clients, IRC, email or other mediums where users can share files.

AVERT Recommended Updates :

* Office2000 Updates

* Malformed Word Document Could Enable Macro to Run Automatically (Information/Patch )

* scriptlet.typelib/Eyedog vulnerability patch

* Outlook as an email attachment security update

* Exchange 5.5 post SP3 Information Store Patch 5.5.2652.42 - this patch corrects detection issues with GroupShield

For a list of attachments blocked by the Outlook patch and a general FAQ, visit this link .
Additionally, Network Administrators can configure this update using an available tool - visit this link for more information .

It is very common for macro viruses to disable options within Office applications for example in Word, the macro protection warning commonly is disabled. After cleaning macro viruses, ensure that your previously set options are again enabled.