After two years of decline in Android ransomware, a new family has emerged. ESET has seen the ransomware, detected by ESET Mobile Security as Android/Filecoder.C, distributed via various online forums. Using victims’ contact lists, it spreads further via SMS with malicious links. Due to narrow targeting and flaws in both execution of the campaign and implementation of its encryption, the impact of this new ransomware is limited. However, if the developers fix the flaws and the operators start targeting broader groups of users, the Android/Filecoder.C ransomware could become a serious threat.

REFERENCE:
https://www.welivesecurity.com/2019/07/29/android-ransomware-back/