Penetration testing is necessary to determine the true attack footprint of your environment. It may often be confused with vulnerability assessment, and thus, it is important that the differences are fully explained to your clients.
Vulnerability assessments are necessary to discover potential vulnerabilities throughout the environment. There are many tools available that automate this process so that even an inexperienced security professional or administrator can effectively determine the security posture of their environment. Depending on the scope, additional manual testing may also be required. Full exploitation of systems and services is not generally in the scope of a normal vulnerability assessment engagement.
Systems are typically enumerated and evaluated for vulnerabilities, and testing can often be done with or without authentication. Most vulnerability management and scanning solutions provide actionable reports...