Account Access Removal
Where this stands
One published detection covers this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
Adversaries may interrupt availability of system and network resources by inhibiting access to accounts utilized by legitimate users. Accounts may be deleted, locked, or manipulated (ex: changed credentials, revoked permissions for SaaS platforms such as Sharepoint) to remove access to accounts. Adversaries may also subsequently log off and/or perform a System Shutdown/Reboot to set malicious changes into place. In Windows, Net utility, Set-LocalUser and Set-ADAccountPassword PowerShell cmdlets may be used by adversaries to modify user accounts. Accounts could also be disabled by Group Policy. In Linux, the passwd utility may be used to change passwords. On ESXi servers, accounts can be removed or modified via esxcli (system account set, system account remove). Adversaries who use ransomware or similar attacks may first perform this and other Impact behaviors, such as Data Destruction and Defacement, in order to impede incident response/recovery before completing the Data Encrypted for Impact objective.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0334
Correlated user account modification (reset, disable, deletion) events with anomalous process lineage (e.g., PowerShell or net.exe from an interactive session), especially outside of IT admin change windows or by non-admin users.
- AN0335
Password changes or account deletions via 'passwd', 'userdel', or 'chage' preceded by interactive shell or remote command execution from non-privileged accounts.
- AN0336
Execution of dscl or sysadminctl commands to disable, delete, or modify users combined with anomalous process ancestry or terminal session launch.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.