Analyze and discuss a case where Company A claims its network was compromised by a connection from Company B network. How should both companies proceed? Who should be involved?

https://securityintelligence.com/dealing-with-third-party-vendor-connections-in-your-network/

https://www.scmagazine.com/ask-partner-network-compromised-again-to-spread-malware/article/645637/