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E X P L O I T A T I O N   U S I N G  

C L I E N T - S I D E   A T T A C K S

Years of focus on defensive network perimeters have 
drastically shrunk the traditional attack surfaces. When 
one avenue of attack becomes too difficult to penetrate, 
attackers can find new and easier methods for attack-
ing their targets. Client-side attacks were the next evo-
lution of attacks after network defenses became more

prominent. These attacks target software commonly installed on computers 
in such programs as web browsers, PDF readers, and Microsoft Office appli-
cations. Because these programs are commonly installed on computers out 
of the box, they are obvious attack vectors for hackers. It’s also common for 
these applications to be out of date on users’ machines because of irregular 
patching cycles. Metasploit includes a number of built-in client-side exploits, 
which we’ll cover in depth in this chapter.

If you can bypass all the protective countermeasures a company has 

in place and infiltrate a network by tricking a user into clicking a malicious 
link, you have a much better chance of achieving a compromise. Suppose, for 
example, that you are performing a covert penetration test against a corpo-
rate target using social engineering. You decide that sending a phishing email