Wlrmdr.exe

Windows Logon Reminder executable

Paths

• c:\windows\system32\wlrmdr.exe

Commands

Execute

Execute executable with wlrmdr.exe as parent process

Use case: Use wlrmdr as a proxy binary to evade defensive countermeasures

Privileges: User

wlrmdr.exe -s 3600 -f 0 -t _ -m _ -a 11 -u {PATH:.exe}

Detection

• Sigma: https://github.com/SigmaHQ/sigma/blob/683b63f8184b93c9564c4310d10c571cbe367e1e/rules/windows/process_creation/proc_creation_win_lolbin_wlrmdr.yml
• IOC: wlrmdr.exe spawning any new processes

Resources

• https://twitter.com/0gtweet/status/1493963591745220608
• https://twitter.com/Oddvarmoe/status/927437787242090496
• https://twitter.com/falsneg/status/1461625526640992260
• https://docs.microsoft.com/en-us/windows/win32/api/shellapi/ns-shellapi-notifyicondataw