How to Block the Malicious Access to Android External Storage

摘要: External storage (e.g., SD card) is an important component of the Android mobile terminals, commonly used for storing user information (including sensitive data such as photos). However, current protection mechanisms permission mechanism) on external are somehow coarse-grained, where controlled a whole, which means all files accessible once assigned to APP. This coarse-grained control weakness could be easily leveraged by attackers. For example, ransomware can obtain access and encrypt stealthily ransom. In this paper, we introduce Access Control List (ACL) mechanism enforce fine-grained storage. With ACL, policy defined at file granularity, permissions will only granted legitimate APPs specified in white list. First, activate Linux ACL system extend it Filesystem Userspace (FUSE). Because built FUSE filesystem, different from traditional filesystems EXT4) thus not supported mechanism. Second, ACL-policy configuration interface framework, enables device owner APP developers set policies their Finally, implement prototype based Nexus 6 devices deployed 6.0.1 kernel 3.10.4, evaluate stability, effectiveness performance. The results show our effectively prevent illegal with negligible performance overhead. As far know, first work that really Android.