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.

Aliases

• CSL

• CSL-457

• CSL.457

Characteristics

CSL.381/457 is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM.

Upon infection, the virus becomes memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 12's return is moved..

Once memory resident, it infects .COM files as they are executed.

Additional Comments:
The CSL, or MicroElephant, virus was submitted in November, 1991. This virus is a memory resident infector of .COM programs, including COMMAND.COM. When the first CSL infected program is executed, the virus will install itself memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 12's return will have been moved, however there will appear to be no change in total system and available free memory as indicated by the DOS CHKDSK program. After CSL has become memory resident, it will infect .COM programs when they are executed. If COMMAND.COM is executed, it will also become infected. CSL infected programs will have a file length increase of 457 bytes with the virus being located at the end of the infected file. The program's date and time in a DOS disk directory listing will not be altered. The following text string can be found within the viral code in infected programs: "Microelephant V6 by CSL" Systems infected with CSL may experience the message "Bad Command or file name", and a return to the DOS prompt, when the user attempts to execute .EXE programs over approximately 64K in size. The .EXE programs themselves have not been altered, but it is the virus in memory returning the message. CSL doesn't do anything besides replicate and interfer with .EXE program execution. Known variant(s) of CSL are:

Symptoms

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

"Microelephant V6 by CSL.381/457"

Systems infected with CSL.381/457 may experience the message "Bad Command or file name", and a return to the DOS prompt, when the user attempts to execute .EXE files over approximately 64K in size. The .EXE files themselves have not been altered, but the virus in memory returning the message.

CSL.381/457 infected files have a file length increase of 457 bytes. The virus is located at the end of the infected file. The file's date and time in a 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

• CSL.381
• CSL.517

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.

Aliases

• CSL

• CSL-457

• CSL.457

Characteristics

Characteristics -

CSL.381/457 is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM.

Upon infection, the virus becomes memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 12's return is moved..

Once memory resident, it infects .COM files as they are executed.

Additional Comments:
The CSL, or MicroElephant, virus was submitted in November, 1991. This virus is a memory resident infector of .COM programs, including COMMAND.COM. When the first CSL infected program is executed, the virus will install itself memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 12's return will have been moved, however there will appear to be no change in total system and available free memory as indicated by the DOS CHKDSK program. After CSL has become memory resident, it will infect .COM programs when they are executed. If COMMAND.COM is executed, it will also become infected. CSL infected programs will have a file length increase of 457 bytes with the virus being located at the end of the infected file. The program's date and time in a DOS disk directory listing will not be altered. The following text string can be found within the viral code in infected programs: "Microelephant V6 by CSL" Systems infected with CSL may experience the message "Bad Command or file name", and a return to the DOS prompt, when the user attempts to execute .EXE programs over approximately 64K in size. The .EXE programs themselves have not been altered, but it is the virus in memory returning the message. CSL doesn't do anything besides replicate and interfer with .EXE program execution. Known variant(s) of CSL are:

Symptoms

Symptoms -

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

"Microelephant V6 by CSL.381/457"

Systems infected with CSL.381/457 may experience the message "Bad Command or file name", and a return to the DOS prompt, when the user attempts to execute .EXE files over approximately 64K in size. The .EXE files themselves have not been altered, but the virus in memory returning the message.

CSL.381/457 infected files have a file length increase of 457 bytes. The virus is located at the end of the infected file. The file's date and time in a 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 -

• CSL.381
• CSL.517