Zindos

Classification

Malware

Worm

W32

W32/Zindos.A

Summary

The Zindos worm used the backdoor that was installed by the Mydoom.M worm, that spread earlier. Since Zindos had no other infection vector, so it could only spread to computers that were infected with Mydoom.M earlier. It even used a list of infected computers, collected by Mydoom. I suppose the idea was to use the mass-mailing worm to pave way to the payload for rapid distribution later. The Zindos code had not much to do, just go straight through the list of already compromised computers and copy itself there through the backdoor. Zindos is a network worm which spreads with the help of the Mydoom.M mass-mailing worm. For more information, see Mydoom.M.

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.

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Submit a sample

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Technical Details

Mydoom.M plants a backdoor that scans for other systems with the same backdoor. Zindos uses the backdoor and its target list to spread. The payload is a Distributed Denial-of-Service (DDOS) attack against www.microsoft.com.

System Infection

Zindos first arrives through the Mydoom.M backdoor. When uploaded to the victim, the worm file is dropped to the TEMP folder with a random name. The file is added to the registry as either of

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
 "Tray" = "%TEMP%\.exe"
 

Propagation

To propagate Zindos uses the list of compromised computers collected by the Mydoom.M backdoor. The worm goes through the list and uploads itself with the corresponding command through the backdoor.

Payload

The payload of Zindos is a Distributed Denial-of-Service routine that downloads http://www.microsoft.com/ in an infinite loop with 50ms delays.