F-Secure Trojan Information Pages : RommWar.A [ Summary ] | [ Disinfection ] | [ Detailed Description ] | [ Detection ] Name: RommWar.A Type: Trojan Category: Trojan Platform: SymbOS Date of Discovery: April 02, 2006 Summary SymbOS/RommWar.A is a malicious SIS trojan that installs a malfunctioning system component that cause different behaviour depending on the ROM software version in the device. Different effects witnessed range from freezing of the device requiring a restart, to disabling the power button on the device, or in some cases no apparent effect on device at all. Disinfection Manual disinfection Depending on the effect caused by SymbOS/RommWar.A, removal of the malfunctioning components might be possible by going to application manager and uninstalling the SIS file in which SymbOS/RommWar.A arrived. Disinfection for the cases when phone cannot start up CAUTION! this method will remove all data on the device including calendar and phone numbers: Power off the phone Hold the following three buttons down - "answer call" + "*" + "3" Keep holding down the buttons and power on the phone Depending on the model, you will either get text that reads "formatting" or a start-up dialog that asks for the initial phone settings Your phone is now formatted and can be used again Back to the Top Detailed Description Installation to System SymbOS/RommWar.A installs a malfunctioning system binary into the C: drive of the phone and a bootstrap component that executes the malfunctioning system binary. This is followed by different effect depending on the version of the ROM software in the device. Effects witnessed vary from the freezing of the device, to disabling of the power button, or sometimes no apparent effect at all. Payload Installs a corrupted system binary and a bootstrap component. In the case of freezing the device, shortly after the device infected with SymbOS/RommWar.A restarts, it shows a notification similar to the picture above. When this notification is displayed the only working function on the device is the option to power-off. Back to the Top Detection F-Secure Mobile Anti-Virus for Symbian detects this malware starting from the update build number 84. Back to the Top Write-up: Juha-Pekka Heikkilä, April 6, 2006 Technical Details: Juha-Pekka Heikkilä, April 6, 2006 F-Secure Corporation