Backdoors and Trojans

In its simplest sense, a backdoor is a way for an attacker to get back into a network or system without being detected. A backdoor is a hidden passage way back into a system that requires minimal effort to exploit. As we stated earlier, after an attacker performs reconnaissance by scanning and successfully exploiting a system, he wants to make it easier to get back in at a later time. One of the most common ways to create a backdoor is by opening up a port that has a listening agent attached. These programs are covered next. An open port is fairly easy to detect, if a company is looking in the right places. If a company runs a port scan against every system and scans for open ports from 1 through 1023, and an attacker has ...

Get Hackers Beware now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.