Adversaries may gain persistence and elevate privileges by executing malicious content triggered by PowerShell profiles. A PowerShell profile (profile.ps1) is a script that runs when PowerShell starts and can be used as a logon script to customize user environments.
PowerShell supports several profiles depending on the user or host program. For example, there can be different profiles for PowerShell host programs such as the PowerShell console, PowerShell ISE or Visual Studio Code. An administrator can also configure a profile that applies to all users and host programs on the local computer. [1]
Adversaries may modify these profiles to include arbitrary commands, functions, modules, and/or PowerShell drives to gain persistence. Every time a user opens a PowerShell session the modified script will be executed unless the -NoProfile flag is used when it is launched. [2]
An adversary may also be able to escalate privileges if a script in a PowerShell profile is loaded and executed by an account with higher privileges, such as a domain administrator. [3]
| ID | Name | Description |
|---|---|---|
| G0010 | Turla |
Turla has used PowerShell profiles to maintain persistence on an infected machine.[2] |
| ID | Mitigation | Description |
|---|---|---|
| M1045 | Code Signing |
Enforce execution of only signed PowerShell scripts. Sign profiles to avoid them from being modified. |
| M1022 | Restrict File and Directory Permissions |
Making PowerShell profiles immutable and only changeable by certain administrators will limit the ability for adversaries to easily create user level persistence. |
| M1054 | Software Configuration |
Avoid PowerShell profiles if not needed. Use the -No Profile flag with when executing PowerShell scripts remotely to prevent local profiles and scripts from being executed. |
| ID | Data Source | Data Component |
|---|---|---|
| DS0017 | Command | Command Execution |
| DS0022 | File | File Creation |
| File Modification | ||
| DS0009 | Process | Process Creation |
Locations where profile.ps1 can be stored should be monitored for new profiles or modifications. [4][5] Example profile locations (user defaults as well as program-specific) include:
$PsHome\Profile.ps1$PsHome\Microsoft.{{HostProgram}}_profile.ps1$Home\[My ]Documents\PowerShell\Profile.ps1$Home\[My ]Documents\PowerShell\Microsoft.{{HostProgram}}_profile.ps1Monitor abnormal PowerShell commands, unusual loading of PowerShell drives or modules, and/or execution of unknown programs.