Its well known that battleye proxies calls to `NtReadVirtualMemory/NtWriteVirtualMemory` to their driver via DeviceIoControl in both `lsass.exe` and `csrss.exe`. Although csrss.exe
is not something you can inject from usermode, lsass.exe is (although it can be protected, depends on your system/hvci).
The reason this proxy of a syscall is a vulnerability is simply because their is no validation of R/W access on the specified handle passed to `BEDaisy`. In other words: you can
open a handle with `PROCESS_QUERY_LIMITED_INFORMATION` and use that handle to read/write any usermode memory that is also read/writeable. The handle access is not important to bedaisy
This section will go into detail about what exactly is going on here. csrss.exe/lsass.exe have handles to all processes and since battleye strips the R/W access of the handle that these processes have
to the game... thus they proxy the calls to their driver.