Malware
Malware authors target bugs, or loopholes, to exploit. A common method is exploitation of a buffer overrun vulnerability, where software designed to store data in a specified region of memory does not prevent more data than the buffer can accommodate being supplied. Malware may provide data that overflows the buffer, with malicious executable code or data after the end; when this payload is accessed it does what the attacker, not the legitimate software, determines.
Brain Test
The malware is thought to have been written by Chinese actor, according to Shaulov of Check Point, based on the use of a packing/obfuscation tool from Baidu. Eleven Paths, a Telefonica-owned company, found links to may other pieces of malware, based on the id used to access Umeng, Internet domains accessed by the apps and shared jpg and png images.