T0859 Valid Accounts — Detection Rules

Source-backed rule directory

No reviewed association in this snapshot.

Atlas deterministic concepts

No exact concept selected.

Anomaly models

No exact Atlas model in this snapshot.

ATT&CK analytic guidance

DET0724 Detection of Valid Accounts

AN1857 Analytic 1857

Real-time monitoring identifies an Industrial Control System (ICS)-role account authenticating via interactive or remote logon from a workstation not in the approved host inventory, or outside the account's established usage pattern, immediately followed within a short window by that session connecting to the field device network or ICS application. OT operational-fidelity gate: Alert only when the account/device/session violates the approved identity + source host/jump path/zone policy and is corroborated by access to a protected OT asset, execution, configuration change, or another security-relevant follow-on event. Suppress approved shift activity, vendor support, break-glass use, commissioning, and documented remote-access windows.

AN2122 Analytic 2122

Real-time monitoring identifies Secure Shell (SSH) or local authentication by an Industrial Control System (ICS) service or operator account from a source Internet Protocol (IP) address outside the approved administrative Classless Inter-Domain Routing (CIDR) subnet, or a sudo/su escalation event by an ICS service account that does not normally require interactive privilege escalation, correlated with subsequent execution of ICS engineering tools. OT operational-fidelity gate: Alert only when the account/device/session violates the approved identity + source host/jump path/zone policy and is corroborated by access to a protected OT asset, execution, configuration change, or another security-relevant follow-on event. Suppress approved shift activity, vendor support, break-glass use, commissioning, and documented remote-access windows.

AN2182 Analytic 2182

Real-time monitoring identifies network device management session authentication such as Secure Shell (SSH), Remote Authentication Dial-In User Service (RADIUS), and Terminal Access Controller Access-Control System Plus (TACACS+) using valid Industrial Control System (ICS) network administrator credentials but originating from source IPs outside the approved Network Management System (NMS) Classless Inter-Domain Routing (CIDR) subnet or at times inconsistent with the account's normal usage pattern, where the session performs configuration changes not reflected in any open change-control ticket. OT operational-fidelity gate: Alert only when the account/device/session violates the approved identity + source host/jump path/zone policy and is corroborated by access to a protected OT asset, execution, configuration change, or another security-relevant follow-on event. Suppress approved shift activity, vendor support, break-glass use, commissioning, and documented remote-access windows.

AN2217 Analytic 2217

Real-time monitoring identifies field device access (Industrial Control System (ICS) protocol sessions, management interface authentication) using credentials or authentication tokens associated with a legitimate engineering account, but from a source Internet Protocol (IP) address or Media Access Control (MAC) address not enrolled as an authorized engineering workstation, where the authenticated session subsequently performs write operations the credential owner has not acknowledged via change control. OT operational-fidelity gate: Alert only when the account/device/session violates the approved identity + source host/jump path/zone policy and is corroborated by access to a protected OT asset, execution, configuration change, or another security-relevant follow-on event. Suppress approved shift activity, vendor support, break-glass use, commissioning, and documented remote-access windows.