Travelling the Hypervisor and SSD: A Tag-Based Approach Against Crypto Ransomware with Fine-Grained Data Recovery

Ransomware has evolved from an economic nuisance to a national security threat nowadays, which poses a significant risk to users. To address this problem, we propose RansomTag, a tag-based approach against crypto ransomware with fine-grained data recovery. Compared to state-of-the-art SSD-based solutions, RansomTag makes progress in three aspects. First, it decouples the ransomware detection functionality from the firmware of the SSD and integrates it into a lightweight hypervisor of Type I. Thus, it can leverage the powerful computing capability of the host system and the rich context information, which is introspected from the operating system, to achieve accurate detection of ransomware attacks and defense against potential targeted attacks on SSD characteristics. Further, RansomTag is readily deployed onto desktop personal computers due to its parapass-through architecture. Second, RansomTag bridges the semantic gap between the hypervisor and the SSD through the tag-based approach proposed by us. Third, RansomTag is able to keep 100% of the user data overwritten or deleted by ransomware, and restore any single or multiple user files to any versions based on timestamps. To validate our approach, we implement a prototype of RansomTag and collect 3,123 recent ransomware samples to evaluate it. The evaluation results show that our prototype effectively protects user data with minimal scale data backup and acceptable performance overhead. In addition, all the attacked files can be completely restored in fine-grained.