Suspicious FortiGate Rogue Admin with Unrestricted Trusthost (via fortigate)

ATT&CK techniques

Initial Access → Defense Evasion

Recon
Resource Dev
Initial Access
- T1078.001Default Accounts
Execution
Persistence
- T1078.001Default Accounts
- T1136.001Local Account
Priv Esc
- T1078.001Default Accounts
Defense Evasion
- T1078.001Default Accounts
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects FortiGate configuration events that create or modify an administrator account with a trusthost of 0.0.0.0/0, allowing management access from any source address. Threat actors used rogue admins such as support, ssl-admin, and helpdesk with wide-open trusthosts to keep access to compromised appliances. An admin with an unrestricted trusthost is a strong persistence and access indicator.

Reporting behind it

Related detections9 linkedT1136.001 — drag to rearrange

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Malicious Local Administrator Account Added via net localgroup (via process_creation)

Malicious Switch User to Rogue Root-Equivalent Account troot (via process_creation)

Malicious Rogue F5 BIG-IP Administrator Account Creation via tmsh (via process_creation)

Suspicious Hidden Local Account Creation SqlDbAdmin via Process Creation

Suspicious FortiGate Rogue Admin with Unrestricted Trusthost (via fortigate)

Pivot detection · T1136.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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