Suspicious Hidden Account Creation via Winlogon SpecialAccounts UserList Registry

ATT&CK techniques

Initial Access → Defense Evasion

Recon
Resource Dev
Initial Access
- T1078.003Local Accounts
Execution
Persistence
- T1078.003Local Accounts
Priv Esc
- T1078.003Local Accounts
Defense Evasion
- T1078.003Local Accounts
- T1564.002Hidden Users
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects modification of the Winlogon SpecialAccounts UserList registry key to hide a local account from the Windows logon screen. The Chaos ransomware-as-a-service group sets a user value to 0 under this key to conceal accounts created for persistent access. Hiding accounts from the logon interface is a defense-evasion technique used to maintain covert access.

Reporting behind it

Related detections9 linkedT1564.002 — drag to rearrange

Hiding local user accounts

Malicious Hidden Local Account via Winlogon SpecialAccounts UserList

Suspicious Hidden Local Account via SpecialAccounts UserList Registry Value (via registry_set)

macOS dseditgroup Used to Add User to admin Group

macOS Root Account Enable Attempt via dsenableroot

macOS sysadminctl Used to Add User to Admin Group

macOS dscl Adds User to Admin Group via -append /Groups/admin GroupMembership

Windows Process Creation: Suspicious secedit.exe Security Policy Export or Configuration

Windows Registry: Hidden User via Winlogon SpecialAccounts Userlist Value 0

Suspicious Hidden Account Creation via Winlogon SpecialAccounts UserList Registry

Pivot detection · T1564.002 · 9 related

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