In the Equifax data breach case, hackers initially gained access to their corporate data through:

Sending phishing emails to Equifax execs to gain administrative password access

The theft of a senior managers laptop computer containing valuable password and customer information

An SQL injection

Accessing a third$-$party vendor's system who had access to Equifax's system

Failure to apply software patches $($e$.$g$.,$ Apache Strut$)$ in a consistent manner