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

• Flex

Characteristics

Flex.491 is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM.

Upon infection, the Flex.491 virus becomes memory resident at the top of system memory but below the 640K DOS boundary. Interrupts 09 and 21are hooked by the Flex.491 virus.

Once the Flex.491 virus is memory resident, it infects .COM files, including COMMAND.COM, as they are executed.

Additional Comments:
The Flex virus was submitted in January, 1993. Flex is a memory resident infector of .COM programs, including COMMAND.COM. It is from North America. When the first Flex infected program is executed, the Flex 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 1,008 bytes. Interrupts 09 and 21 will be hooked by the Flex virus. Once the Flex virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed. Infected programs will have a file length increase of 491 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 is visible within the viral code in all Flex infected programs: "[FLEX]" The Flex virus may occassionally display the following message on the system monitor: "Flex-It-Up gal!" "Time to have sex!" "Admiral Bailey" These text strings are encrypted within the viral code.

Symptoms

The following text string is visible within the viral code in all Flex.491 infected files:

"[FLEX]"

The Flex.491 virus occasionally displays the following message on the system monitor:

"Flex-It-Up gal!"
"Time to have sex!"
"Admiral Bailey"

These text strings are encrypted within the viral code.

Total system and available free memory decreases by 1,008 bytes. Infected files have a file length increase of 491 bytes. The virus is located at the end of the file. The file's date and time in the DOS disk directory listing is 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.

Aliases

• Flex

Characteristics

Characteristics -

Flex.491 is a memory resident, file infecting virus. It infects .COM files, including COMMAND.COM.

Upon infection, the Flex.491 virus becomes memory resident at the top of system memory but below the 640K DOS boundary. Interrupts 09 and 21are hooked by the Flex.491 virus.

Once the Flex.491 virus is memory resident, it infects .COM files, including COMMAND.COM, as they are executed.

Additional Comments:
The Flex virus was submitted in January, 1993. Flex is a memory resident infector of .COM programs, including COMMAND.COM. It is from North America. When the first Flex infected program is executed, the Flex 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 1,008 bytes. Interrupts 09 and 21 will be hooked by the Flex virus. Once the Flex virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed. Infected programs will have a file length increase of 491 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 is visible within the viral code in all Flex infected programs: "[FLEX]" The Flex virus may occassionally display the following message on the system monitor: "Flex-It-Up gal!" "Time to have sex!" "Admiral Bailey" These text strings are encrypted within the viral code.

Symptoms

Symptoms -

The following text string is visible within the viral code in all Flex.491 infected files:

"[FLEX]"

The Flex.491 virus occasionally displays the following message on the system monitor:

"Flex-It-Up gal!"
"Time to have sex!"
"Admiral Bailey"

These text strings are encrypted within the viral code.

Total system and available free memory decreases by 1,008 bytes. Infected files have a file length increase of 491 bytes. The virus is located at the end of the file. The file's date and time in the DOS disk directory listing is 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