If they are not properly walled off, an attacker can use them to break into a system.

The height of the walls would force attackers to use scaling-ladders.

With that, he ran toward the door the other attacker had used.

"This could mean the attackers used a new weapon."

Most attackers had access to and had used weapons prior to the attack.

They said, however, that the attackers did not use racial epithets.

But it's in the spec, so the attackers can use that.

Remember that the attacker cannot use the hands or limbs thus employed to strike you.

The attacker can now use their private key to sign another certificate which may contain arbitrary data.

Using the combination of all three techniques allows the attacker to carry out his plan.