Trojan:SymbOS/Yxe

Classification

Category :

Malware

Type :

Trojan

Platform :

SymbOS

Aliases :

Trojan:​SymbOS/Yxe, Worm.SymbOS.Yxe, SymbOS/Yxes.A!worm (Other)

Summary

Trojan:SymbOS/Yxe is malicious software for Symbian S60 3rd Edition Phones.

Removal

Yxe does not utilize a hidden interface. If the App manager is available, Yxe can be removed. The user only needs to locate the application name that was presented during installation. Example: Sexy View.

The log file (mr.log) and the SISX file (root.sisx) will not be deleted during uninstallation.

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

Symbian S60 3rd Edition

Trojan:SymbOS/Yxe variants are complied for S60 3rd Edition phones. The installation file will not install on older Symbian phones.

Yxe variants have been Symbian signed using a valid certificate. They will install normally on S60 3rd Edition phones.

The certificate used by Yxe are in the process of being revoked. The disinfection section contains additional details regarding certificates.

Variants of Trojan:SymbOS/Yxe include:

  • Trojan:SymbOS/Yxe.A
  • Trojan:SymbOS/Yxe.B
  • Trojan:SymbOS/Yxe.C

Installation

Social engineering is used to entice the user into installing Yxe.

The installer prompts the user to install "Sexy View" by the vendor "Play Boy".

The user is offered English and Chinese language options. However, there is no user interface.

Actions

Yxe attempts to terminate:

  • AppMngr

Yxe attempts to avoid debugging and terminates the processes of many third party file/process viewing utilities.

  • ActiveFile
  • TaskMan
  • TaskSpy
  • Y-Tasks

Yxe collects data about the phone.

It will attempt to open an HTTP connection in order to upload the data and keeps the connection open at all times.

The domain list to which Yxe attempts to connect is encrypted within the code of Yxe.

Once connected it starts writing a log file called mr.log. It creates a sis file named "c:\data\root.sisx".

Yxe modifies the file C:\system\data\System.ini.

It will attempt to send SMS messages to the phone's contact list.

It starts automatically when the phone boots.

Removal

Trojan:SymbOS/Yxe will uninstall itself. The name in the application manager depends on the variant.

The name "Sexy View" has been used by early Yxe variants. See the disinfection section for additional details.