Token Impersonation/Theft

What the technique is

Adversaries may duplicate then impersonate another user's existing token to escalate privileges and bypass access controls. For example, an adversary can duplicate an existing token using DuplicateToken or DuplicateTokenEx. The token can then be used with ImpersonateLoggedOnUser to allow the calling thread to impersonate a logged on user's security context, or with SetThreadToken to assign the impersonated token to a thread. An adversary may perform Token Impersonation/Theft when they have a specific, existing process they want to assign the duplicated token to. For example, this may be useful for when the target user has a non-network logon session on the system. When an adversary would instead use a duplicated token to create a new process rather than attaching to an existing process, they can additionally Create Process with Token using CreateProcessWithTokenW or CreateProcessAsUserW. Token Impersonation/Theft is also distinct from Make and Impersonate Token in that it refers to duplicating an existing token, rather than creating a new one.

What MITRE says you would watch

• AN1324

  Detection of token duplication and impersonation attempts by correlating suspicious command-line executions (e.g., runas) with API calls to DuplicateToken, DuplicateTokenEx, ImpersonateLoggedOnUser, or SetThreadToken. The chain includes the initial command execution or in-memory API invocation → token handle duplication or thread token assignment → a new or existing process assuming the impersonated user's context.