This article provides an educational overview of PsExec, a Windows utility for executing commands on remote systems using valid user credentials. It discusses the process of performing penetration testing using PsExec, including scanning for SMB services, brute-forcing user credentials, and utilizing PsExec.py for executing commands remotely. Lastly, it highlights the importance of not triggering anti-virus defenses and ensuring message signing is enabled to enhance security. Affected: Windows systems, SMB protocol
Keypoints :
- PsExec is a Windows utility by Microsoft for executing commands on remote systems using user credentials.
- The tool operates through the SMB protocol and requires user authentication.
- Initial port scanning helps to determine if SMB is running on the target system and if message signing is required.
- If SMB does not require message signing, multiple attacks such as NTLM Relay and Pass-The-Hash are possible.
- Brute-force attacks on SMB can be performed using Metasploit with the appropriate settings.
- PsExec is a portable executable and cannot run natively on Linux; however, it can be executed using Wine.
- A Python script called PsExec.py can be used to replicate PsExec functionalities, requiring the Impacket library.
- PsExec.py allows for command execution on remote machines after authenticating with valid credentials or hashes.
- This method utilizes legitimate Windows utilities for authentication, reducing the chance of detection.
- Extending functionality to gain a Meterpreter session can be done but may raise detection risks.
- Important security lesson: Always enable required message signing to enhance system security.