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

Scroll is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM. It employs some stealth techniques to avoid the user noticing the file infections.

Upon infection, the Scroll virus becomes memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 21 is hooked by Scroll in memory.

Once memory resident, the Scroll virus infects .COM files, as they are executed or opened.

Additional Comments:
The Scroll virus was received from Manchester, England in October, 1992. Scroll is a memory resident infector of .COM programs, including COMMAND.COM. It employs some stealth techniques to avoid the user noticing the file infections. The first time a program infected by the Scroll virus is executed, the Scroll virus will install itself memory resident at the top of system memory but below the 640K DOS boundary. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 3,008 bytes. Interrupt 21 will be hooked by Scroll in memory. Once memory resident, the Scroll virus will infect .COM programs, including COMMAND.COM, when they are executed or opened for any reason. Infected programs will have a file length increase of 795 to 1,306 bytes which the virus will hide when it is memory resident. The Scroll virus will be located at the end of infected programs. The seconds field in the file's date and time in the DOS disk directory will have been set to "62", the infection marker for the virus. The following text strings are encrypted within the viral code: "[SCROLL] ICE-9 ARcV" "\COMMAND.COM Systems infected with the Scroll virus may notice that the DOS CHKDSK program will detect file allocation errors when the Scroll virus is memory resident. It will also occassionally overwrite .BAT files, permanently corrupting them.

Symptoms

The following text strings are encrypted within the viral code:

"[SCROLL] ICE-9 ARcV"
"\COMMAND.COM

Users of infected systems may notice that the DOS CHKDSK program detects file allocation errors when the Scroll virus is memory resident. Scroll occasionally overwrites .BAT files, permanently corrupting them.

Total system and available free memory decreases by 3,008 bytes. Infected files have a file length increase of 795 to 1,306 bytes. The virus hides the file length increase when it is memory resident (Stealth technique). The Scroll virus is located at the end of infected files. The seconds field in the file's date and time in the DOS disk directory is set to "62".

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 -

Scroll is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM. It employs some stealth techniques to avoid the user noticing the file infections.

Upon infection, the Scroll virus becomes memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 21 is hooked by Scroll in memory.

Once memory resident, the Scroll virus infects .COM files, as they are executed or opened.

Additional Comments:
The Scroll virus was received from Manchester, England in October, 1992. Scroll is a memory resident infector of .COM programs, including COMMAND.COM. It employs some stealth techniques to avoid the user noticing the file infections. The first time a program infected by the Scroll virus is executed, the Scroll virus will install itself memory resident at the top of system memory but below the 640K DOS boundary. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 3,008 bytes. Interrupt 21 will be hooked by Scroll in memory. Once memory resident, the Scroll virus will infect .COM programs, including COMMAND.COM, when they are executed or opened for any reason. Infected programs will have a file length increase of 795 to 1,306 bytes which the virus will hide when it is memory resident. The Scroll virus will be located at the end of infected programs. The seconds field in the file's date and time in the DOS disk directory will have been set to "62", the infection marker for the virus. The following text strings are encrypted within the viral code: "[SCROLL] ICE-9 ARcV" "\COMMAND.COM Systems infected with the Scroll virus may notice that the DOS CHKDSK program will detect file allocation errors when the Scroll virus is memory resident. It will also occassionally overwrite .BAT files, permanently corrupting them.

Symptoms

Symptoms -

The following text strings are encrypted within the viral code:

"[SCROLL] ICE-9 ARcV"
"\COMMAND.COM

Users of infected systems may notice that the DOS CHKDSK program detects file allocation errors when the Scroll virus is memory resident. Scroll occasionally overwrites .BAT files, permanently corrupting them.

Total system and available free memory decreases by 3,008 bytes. Infected files have a file length increase of 795 to 1,306 bytes. The virus hides the file length increase when it is memory resident (Stealth technique). The Scroll virus is located at the end of infected files. The seconds field in the file's date and time in the DOS disk directory is set to "62".

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