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Virus Profile: Python

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Virus Profile information details
Risk Assessment: Home Low | Corporate Low
Date Discovered: 12/1/1994
Date Added: 12/15/1994
Origin: Unknown
Length: 1,142-1,603 Bytes
Type: Virus
Subtype: File Infector
DAT Required: 4002
Removal Instructions
   
 
 
   

Description

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.

Indication of Infection

The following text string is encrypted within the viral code:

"PYTHON"

Execution of the DOS CHKDSK program with the Python virus memory resident results in file allocation errors being indicated on all infected files.

Total system and available free memory decreases by 1,024 bytes. Infected files have a file length increase of approximately 1,142 to 1,603 bytes. The virus is located at the end of the file. The file length increase is hidden by the virus when memory resident (Stealth techniques). The file's date and time in the DOS disk directory listing are altered, the seconds field is set to "40".

Methods 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.
   

Virus Characteristics

Python is a polymorphic, stealth, file infecting virus. It infects .COM and .EXE files, including COMMAND.COM.

Upon infection, this virus may becomes memory resident at the top of system memory but below the 640K DOS boundary.

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

Additional Comments:
The Python virus was received in December, 1994. Its origin or point of isolation is unknown. Python is a polymorphic stealth virus which infects .COM and .EXE files, including COMMAND.COM. When the first Python infected program is executed, this virus may install itself memory resident at the top of system memory but below the 640K DOS boundary. It does not always install itself memory resident, and the system user may have to execute an infected program several times in order for the virus to become memory resident. When resident, total system and available free memory, as indicated by the DOS CHKDSK program from DOS 3.3, will have decreased by 1,264 bytes. Memory mapping utilities will not indicate that any interrupts are hooked by this area of memory. Once the Python virus is memory resident, it will infect .COM and .EXE programs when they are executed. Infected programs will have a file length increase of approximately 1,142 to 1,603 bytes with the virus being located at the end of the file. The file length increase, however, is hidden by the virus when memory resident. The program's date and time in the DOS disk directory listing will not appear to be altered, though the seconds field will have been set to "40". The following text string is encrypted within the viral code: "PYTHON" Execution of the DOS CHKDSK program with the Python virus memory resident will result in file allocation errors being indicated on all infected files.

   
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:

SCANPM /ADL /CLEAN /ALL

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.

   

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