Vulnerability assessment and penetration testing are key tools for evaluating the security of your infrastructure. Such tests can inadvertently crash routers, switches, and printer devices. In worst-case scenarios, these products have caused whole networks to crash, and penetration tests have exposed sensitive company data. With vulnerability scanning, some devices can “just fall over and die when being probed for a completely unrelated issue,” says Secure Network Technologies’ Steve Stasiukonis. The best practice is to run a vulnerability assessment, update your patches based on the findings, then have a penetration tester come in and do his or her thing.”]
Source: https://www.darkreading.com/analytics/third-party-testing-risky-business-