Threat Descriptions

Trojan:WinCE/Redoc

Classification

Category :

Malware

Type :

Trojan

Platform :

WinCE

Aliases :

Trojan:WinCE/Redoc

Summary

Variants in this family are trojans that infect Windows Mobile devices and send SMS messages to premium rate phone numbers, without the user's consent. This results in abnormally high phone charges.

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

This trojan's behavior is reminiscent of the malicious dialers of yesteryear, except that the targeted device is now a mobile device rather than a computer connecting to the Internet via a modem.

Infection

Redoc variants may arrive on the victim's device bundled together with a legitimate application; in which case, it launches the legitimate application to mask the fact the legitimate application's cab file has been infected. Trojan:WinCE/Redoc is a .NET application for mobiles, and uses basic4ppc (a .NET port for Windows Mobile).

Execution

To perform its message sending routine, on execution some Redoc variants will read configuration parameters from a file named setups.dll, a text file that contains the following information:

  • Name of the executable to be launched
  • Number to which SMS messages will be sent
  • Text to include in the SMS message
  • Number of SMS messages to be sent

The steps the trojan follows for its sending routine is simply as follows:

  • When executed, the Trojan launches the executable specified as the first argument of the setups.dll file.
  • The phone number to send the messages to is computed from the second line of the setups.dll file.
  • Each SMS message contains the same text, as configured in the 3rd line of the setups.dll file.
  • The amount of SMS messages sent by the malware depends on the 4th line. This may be 1 or more.

Other Redoc variants have these parameters hard coded.