Shell

Classification

Malware

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Shell, Tentacle_II

Summary

This virus was found in the wild in June 1996 in USA, UK, Australia, Norway and New Zealand. It has possibly been distributed over the internet several times.

Removal

Automatic action

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.

Suspect a file is incorrectly detected (a False Positive)?

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 detection database 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.

Find out more

Knowledge Base

Find the latest advice in our Community Knowledge Base.

User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

A known infection happened on the 3rd of August, 1996, when an infected screen saver called PCTRSHOW.ZIP was posted to the following newsgroups:

alt.sex.pictures
 alt.binaries.pictures.erotica
 alt.binaries.pictures.erotica.blondes
 alt.binaries.pictures.erotica.breasts
 alt.binaries.pictures.erotica.cheerleaders
 alt.binaries.pictures.erotica.female
 alt.binaries.pictures.erotica.lesbians
 alt.binaries.pictures.erotica.oral
 alt.binaries.pictures.erotica.orientals
 alt.binaries.pictures.erotica.redheads
 alt.binaries.pictures.erotica.teen
 alt.binaries.pictures.erotica.teen.female
 alt.binaries.pictures.erotica.voyeurism
 alt.binaries.pictures.erotica.young
 alt.binaries.pictures.groupsex
 alt.binaries.pictures.erotica.latina
 alt.binaries.pictures.celebrities
 alt.binaries.pictures.girls

Do note that there are also clean copies of PCTRSHOW in circulation.

The virus infect only Windows 3.x executables (NE), and it does it without changing the executable entry point. This is an unusual infection method and was first introduced in this virus.

When executed, Shell.10634 searches the directory tree for suitable files to infect. Only EXE and SCR (screen saver) files can get infected.

Also 32bit Win95 and WinNT executables can be infected by the virus, but these files are unable to spread the infection further. Shell not stay resident in memory.

This virus activates by dropping a GIF file, which contains a picture of a Tentacle and text:

I'm the Tentacle Virus!

The author of this virus also wrote the Tentacle and Tentatrickle viruses, which are technically quite different from this virus. See: Tentacle