The IT security team of a company has concerns about network vulnerabilities and hires an external penetration tester to evaluate its security controls and identify potential risks. The company provides the penetration tester with fragments of network information and permits them to use reconnaissance techniques for further information gathering. What penetration testing method is the company using?
1) Known environment penetration testing
2) Partially known environment penetration testing
3) Unknown environment penetration testing
4) Open-source intelligence gathering