Russian security researchers are warning about an Android Trojan called Oldboot that has infected 350,000 devices worldwide.
According to this post at Dr Web, Oldboot has a characteristic that makes it hard to deal with: some of the Trojan's components are loaded into the boot partition of the Android file system. By acting as a bootkit, the researchers claim, it's less likely to be deleted.
The “very unusual” technique involves:
“placing one of the Trojan components into the boot partition of the file system and modifying the init script which is responsible for the initialisation of OS components. When the mobile phone is turned on, this script loads the code of the Trojan Linux-library imei_chk (Dr.Web Anti-virus detects it as Android.Oldboot.1), which extracts the files libgooglekernel.so (Android.Oldboot.2) and GoogleKernel.apk (Android.Oldboot.1.origin) and places them in /system/lib and /system/app, respectively.”
The bootkit operation of Oldboot leads Dr Web to suggest that it's being distributed via corrupted firmware that victims are using to reflash their devices. Once Oldboot is in place, it connects to a remote server to get its instructions – including as they coyly put it “to install or remove certain applications” (El Reg would speculate that apps removed by Oldboot would include security software).
Dr Web says of the 350,000 devices its analysts believe have been infected, 92 per cent are in China. Infections have also been found in Spain, Italy, Germany, Russia, Brazil, the USA and some South East Asian countries. ®