Friday 13th

This page shows details and results of our analysis on the malware Friday 13th

Download Current DAT: 6712

Threat Detail

Malware Type: Virus

Malware Sub-type: File Infector

Discovery Date: 1987-11-01

Next Steps:

Overview
Characteristics
Symptoms
Method of Infection
Removal

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.

Minimum DAT

4002 (1998-12-02)

Updated DAT

4002 (1998-12-02)

Minimum Engine

5.1.00

File Length

512 Bytes

Description Added

1987-11-15

Description Modified

1987-11-15

Malware Proliferation

Characteristics

Friday 13th is a file infecting virus. It does not become memory resident. This virus only infects .COM files. Although it does not infect COMMAND.COM.

Each time an infected file is executed, the virus looks for two other .COM files on the C: drive and one on the A: drive, if found they are infected.

Additional Comments:
The original Friday 13th COM virus first appeared in South Africa in 1987. Unlike the Jerusalem (Friday the 13th) viruses, it is not memory resident, nor does it hook any interrupts. This virus only infects .COM files, but not COMMAND.COM. On each execution of an infected file, the virus looks for two other .COM files on the C: drive and one on the A: drive, if found they are infected. This virus is extremely fast, and the only indication of propagation occurring is the access light being on for the A: drive, if the current default drive is C:. The virus will only infect a .COM file once. The files, after infection, must be less than 64K in length. On every Friday the 13th, if the host program is executed, it is deleted. Known variant(s) of Friday 13th COM are:

Symptoms

The only indication of propagation occurring is the access light being on for the A: drive, if the current default drive is C:. The files, after infection, must be less than 64K in length. Infected files increase in length by 512 bytes.

On every Friday the 13th, if the host file is executed, it is deleted.

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:

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.