Classification

Category :

Malware

Type :

-

Aliases :

Teocatl, Strange Days

Summary

This macro virus infects Office97 Word documents and Excel sheets. It is the second known macro virus that is able to infect several MS Office applications (first was Cross).

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

The code of virus is placed in one module named StrangeDays and contains eight functions. Some of these start automatically under Word (AutoOpen), others start automatically under Excel (Auto_Open).

The virus spreads within applications (Word to Word, Excel to Excel) as well as drops infected files to another application (Word to Excel and Excel to Word).

The virus uses the same VBA program code under both Word and Excel.

The virus uses Import/Export VisualBasic functions: the virus exports its Basic code to the C:\LO.SYS file, and then imports it into documents.

To spread from Word to Excel and vice versa, the virus uses a trick with auto-loading ability of Word and Excel. These applications load templates (Word) and sheets (Excel) from startup directory: to infect Word from Excel the virus creates new NORMAL.DOT (Word) and PERSONAL.XLS (Excel) files in startup directory.

NORMAL.DOT and PERSONAL.XLS contain a small loader program. This loader imports the actualy virus code from the C:\LO.SYS file to NORMAL.DOT or PERSONAL.XLS, depending on the platform.

The virus disables the Tools/Macro, Tools/Options, File/Templates and View/VBCode menu items as well as turns off VisualBasicEditor and VirusProtection. This is done in order to protect the virus from being analyzed. The virus also changes VirusProtection instructions in the system registry.

On 26th of any month, Teocatl displays a dialog box and deletes all files in the current directory. The following text is displayed:

Strange Days by Reptile/29A
 Strange days have found us
 Strange days have tracked us down
 They're going to destroy...