McAfee > Theat Center > Virus Detail Page

Overview

This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.

Characteristics

Mercenary is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM.

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

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

Additional Comments:
The Mercenary virus was submitted in September, 1993. Its origin or point of isolation is unknown. Mercenary is a memory resident infector of .COM programs, including COMMAND.COM. When the first Mercenary infected program is executed, this virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, not moving interrupt 12's return. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 7,040 bytes. Interrupt 21 will be hooked by Mercenary in memory. Once the Mercenary virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed. Infected files will have a file length increase of 854 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 are encrypted within the Mercenary viral code, and are not visible within infected programs: "Mercenry Virii V.1 written by Lupus Yonderboy" "Greets to all of Phalcon / Skism (who don't know i exist)" "Welcome to the wonderful world of VIRII" "You are now in possession of the Mercenry Virii." "By Lupus Yonderboy" "Chaos Mr. Who." "That is our mode and modus" "Hail to the Succubi"

Symptoms

The following text strings are encrypted within the Mercenary viral code, and are not visible within infected files:

"Mercenry Virii V.1 written by Lupus Yonderboy"
"Greets to all of Phalcon / Skism (who don't know i exist)"
"Welcome to the wonderful world of VIRII"
"You are now in possession of the Mercenary Virii."
"By Lupus Yonderboy"
"Chaos Mr.Who."
"That is our mode and modus"
"Hail to the Succubi"

Total system and available free memory decreases by 7,040 bytes. Infected files have a file length increase of 854 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.

Method of Infection

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.

Removal

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.

Variants

Variants

N/A

All Information

Overview -

This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.

Characteristics

Characteristics -

Mercenary is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM.

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

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

Additional Comments:
The Mercenary virus was submitted in September, 1993. Its origin or point of isolation is unknown. Mercenary is a memory resident infector of .COM programs, including COMMAND.COM. When the first Mercenary infected program is executed, this virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, not moving interrupt 12's return. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 7,040 bytes. Interrupt 21 will be hooked by Mercenary in memory. Once the Mercenary virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed. Infected files will have a file length increase of 854 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 are encrypted within the Mercenary viral code, and are not visible within infected programs: "Mercenry Virii V.1 written by Lupus Yonderboy" "Greets to all of Phalcon / Skism (who don't know i exist)" "Welcome to the wonderful world of VIRII" "You are now in possession of the Mercenry Virii." "By Lupus Yonderboy" "Chaos Mr. Who." "That is our mode and modus" "Hail to the Succubi"

Symptoms

Symptoms -

The following text strings are encrypted within the Mercenary viral code, and are not visible within infected files:

"Mercenry Virii V.1 written by Lupus Yonderboy"
"Greets to all of Phalcon / Skism (who don't know i exist)"
"Welcome to the wonderful world of VIRII"
"You are now in possession of the Mercenary Virii."
"By Lupus Yonderboy"
"Chaos Mr.Who."
"That is our mode and modus"
"Hail to the Succubi"

Total system and available free memory decreases by 7,040 bytes. Infected files have a file length increase of 854 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.

Method of Infection

Method of Infection -

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.

Removal -

Removal -

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.

Variants

Variants -

N/A