true_image_2020

An issue was discovered in Acronis True Image 2020 24.5.22510. anti_ransomware_service.exe includes functionality to quarantine files by copying a suspected ransomware file from one directory to another using SYSTEM privileges. Because unprivileged users have write permissions in the quarantine folder, it is possible to control this privileged write with a hardlink. This means that an unprivileged user can write/overwrite arbitrary files in arbitrary folders. Escalating privileges to SYSTEM is trivial with arbitrary writes. While the quarantine feature is not enabled by default, it can be forced to copy the file to the quarantine by communicating with anti_ransomware_service.exe through its REST API.

An issue was discovered in Acronis True Image 2020 24.5.22510. anti_ransomware_service.exe keeps a log in a folder where unprivileged users have write permissions. The logs are generated in a predictable pattern, allowing an unprivileged user to create a hardlink from a (not yet created) log file to anti_ransomware_service.exe. On reboot, this forces the anti_ransomware_service to try to write its log into its own process, crashing in a SHARING VIOLATION. This crash occurs on every reboot.