Commonwealth

Upon infection, Commonwealth becomes memory resident as a low system memory Terminate-and-Stay Resident (TSR) of 2,048 bytes. Interrupt 21 is hooked by the virus in memory.

Once the Commonwealth virus is memory resident, it infects .COM and .EXE files as they are executed.

It is not known what Commonwealth does besides replicate.

Additional Comments:
The Commonwealth virus was received in December, 1993. Its origin or point of isolation is unknown. Commonwealth is a memory resident infector of .COM and .EXE programs, but not COMMAND.COM. When the first Commonwealth infected program is executed, this virus will install itself memory resident as a low system memory TSR of 2,048 bytes. Interrupt 21 will be hooked by the virus in memory. Once the Commonwealth virus is memory resident, it will infect .COM and .EXE programs when they are executed. Infected programs will have a file length increase of 800 to 815 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 appear to be altered, but it will have the seconds field set to "58". The following text string is encrypted within the Commonwealth viral code: "Commonwealth of Independent States" It is unknown what Commonwealth does besides replicate.

"Commonwealth of Independent States"

Infected files have a file length increase of 800 to 815 bytes. The virus is located at the end of the file. The file's date and time in the DOS disk directory listing does not appear to be altered, but the seconds field is set to "58"

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.