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

Merry Xmas is a memory resident, file infecting virus. It infects .EXE files.

Upon infection, the Merry Xmas virus becomes memory resident as a low system memory Terminate-and-Stay Resident (TSR) of 2,016 bytes. Interrupts 21 and 63 are hooked by the virus in memory.

Once the Merry Xmas virus is memory resident, it infects .EXE files as they are executed.

Additional Comments:
The Merry Xmas virus was submitted in April, 1993. Its origin or point of isolation is unknown. Merry Xmas is a memory resident infector of .EXE programs. It plays music during the Christmas season. When the first Merry Xmas infected program is executed, the Merry Xmas virus will install itself memory resident as a low system memory TSR of 2,016 bytes. Interrupts 21 and 63 will be hooked by the virus in memory. Once the Merry Xmas virus is memory resident, it will infect .EXE programs when they are executed. Infected programs will have a file length increase of 1,694 to 1,708 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 string can be found within the Merry Xmas viral code in all infected programs: "Merry Christmas and happy new year ! Written from Tamsui Oxford College." During the Christmas season, the Merry Xmas virus' TSR will be 2,000 bytes in size, and hook interrupts 08, 21, and 63. It will play "Silent Night" on the system speaker, and display the above text string as a message, after the virus has been memory resident for a few minutes. A system hang will then occur.

Symptoms

The following text string is found within the Merry Xmas viral code in all infected files:

"Merry Christmas and happy new year ! Written from Tamsui Oxford College."

During the Christmas season, the Merry Xmas virus' TSR is 2,000 bytes in size, and hook interrupts 08, 21, and 63. It plays "Silent Night" on the system speaker, and display the above text string as a message, after the virus has been memory resident for a few minutes. A system hang also occurs.

Infected files have a file length increase of 1,694 to 1,708 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 -

Merry Xmas is a memory resident, file infecting virus. It infects .EXE files.

Upon infection, the Merry Xmas virus becomes memory resident as a low system memory Terminate-and-Stay Resident (TSR) of 2,016 bytes. Interrupts 21 and 63 are hooked by the virus in memory.

Once the Merry Xmas virus is memory resident, it infects .EXE files as they are executed.

Additional Comments:
The Merry Xmas virus was submitted in April, 1993. Its origin or point of isolation is unknown. Merry Xmas is a memory resident infector of .EXE programs. It plays music during the Christmas season. When the first Merry Xmas infected program is executed, the Merry Xmas virus will install itself memory resident as a low system memory TSR of 2,016 bytes. Interrupts 21 and 63 will be hooked by the virus in memory. Once the Merry Xmas virus is memory resident, it will infect .EXE programs when they are executed. Infected programs will have a file length increase of 1,694 to 1,708 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 string can be found within the Merry Xmas viral code in all infected programs: "Merry Christmas and happy new year ! Written from Tamsui Oxford College." During the Christmas season, the Merry Xmas virus' TSR will be 2,000 bytes in size, and hook interrupts 08, 21, and 63. It will play "Silent Night" on the system speaker, and display the above text string as a message, after the virus has been memory resident for a few minutes. A system hang will then occur.

Symptoms

Symptoms -

The following text string is found within the Merry Xmas viral code in all infected files:

"Merry Christmas and happy new year ! Written from Tamsui Oxford College."

During the Christmas season, the Merry Xmas virus' TSR is 2,000 bytes in size, and hook interrupts 08, 21, and 63. It plays "Silent Night" on the system speaker, and display the above text string as a message, after the virus has been memory resident for a few minutes. A system hang also occurs.

Infected files have a file length increase of 1,694 to 1,708 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