2KKUU7ita

Chapter 8: Network Infrastructure
Understanding Network Infrastructure
Vulnerabilities
Network infrastructure vulnerabilities are the foundation for most technical
security issues in your information systems. These lower-level vulnerabilities
affect practically everything running on your network. That’s why you need
to test for them and eliminate them whenever possible.
Your focus for ethical hacking tests on your network infrastructure should be
to find weaknesses that others can see in your network so you can quantify
your network’s level of exposure.
Many issues are related to the security of your network infrastructure. Some
issues are more technical and require you to use various tools to assess them
properly. You can assess others with a good pair of eyes and some logical
thinking. Some issues are easy to see from outside the network, and others are
easier to detect from inside your network.
When you assess your company’s network infrastructure security, you need
to look at the following:
✓ Where devices, such as a firewall or an IPS, are placed on the network
and how they’re configured
✓ What external attackers see when they perform port scans and how they
can exploit vulnerabilities in your network hosts
✓ Network design, such as Internet connections, remote access capabilities,
layered defenses, and placement of hosts on the network
✓ Interaction of installed security devices, such as firewalls, intrusion prevention
systems (IPSs), antivirus, and so on
✓ What protocols are in use
✓ Commonly attacked ports that are unprotected
✓ Network host configurations
✓ Network monitoring and maintenance
If someone exploits a vulnerability in one of the items in the preceding list or
anywhere in your network’s security, bad things can happen:
✓ A hacker can launch a denial of service (DoS) attack, which can take
down your Internet connection — or your entire network.
✓ A malicious employee using a network analyzer can steal confidential
information in e-mails and files sent over the network.
125