AMD ATI atillk64.sys 5.11.9.0 allows low-privileged users to interact directly with physical memory by calling one of several driver routines that map physical memory into the virtual address space of the calling process. This could enable low-privileged users to achieve NT AUTHORITY\SYSTEM privileges via a DeviceIoControl call associated with MmMapIoSpace, IoAllocateMdl, MmBuildMdlForNonPagedPool, or MmMapLockedPages.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-12138
• https://eclypsium.com/2019/11/12/mother-of-all-drivers/
• https://h0mbre.github.io/atillk64_exploit/