Common Hacker Attack Pathways
In the 2008 Data Breach Investigations Report written by Verizon it discusses the most common methods of access (pathways) used to compromise networks. What they found from the 500+ caseload was the following:

Nearly half of all breaches exploited remote access and control systems. The report states that this is often remote access software (such as PCAnywhere, VNC, Terminal Services, etc.) that the company is leaving open for a 3rd party provider to access and use as needed.
Web applications and Internet-facing systems were also commonly used to exploit systems and networks. This was likely vulnerability exploit and exploit of misconfigured or neglected systems.
Wireless networks were used 9 percent of the time. And in 21 percent of the time, physical access was utilized to compromise the systems. This was most often malicious insiders and 3rd parties.


