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Part III: Hacking Network Hosts
✓ A hacker can set up back-door access into your network.
✓ A hacker can attack specific hosts by exploiting local vulnerabilities
across the network.
Before assessing your network infrastructure security, remember to do the
following:
✓ Test your systems from the outside in, the inside out, and the inside in
(that is, on and between internal network segments and demilitarized
zones [DMZs]).
✓ Obtain permission from partner networks to check for vulnerabilities
on their systems that can affect your network’s security, such as open
ports, lack of a firewall, or a misconfigured router.
Choosing Tools
As with all ethical hacking, your network security tests require the right
tools — you need port scanners, protocol analyzers, and vulnerability assessment
tools. Great commercial, shareware, and freeware tools are available. I
describe a few of my favorite tools in the following sections. Just keep in mind
that you need more than one tool because no tool does everything you need.
If you’re looking for easy-to-use security tools with all-in-one packaging, you
get what you pay for most of the time — especially for the Windows platform.
Tons of security professionals swear by many free security tools, especially
those that run on Linux and other UNIX-based operating systems. Many of
these tools offer a lot of value — if you have the time, patience, and willingness
to learn their ins and outs. It’d behoove you to compare the results of
the free tools with that of their commercial counterparts. I’ve definitely found
some discrepancies.
Scanners and analyzers
These scanners provide practically all the port scanning and network testing
you need:
✓ Cain & Abel (www.oxid.it/cain.html) for network analysis and ARP
poisoning
✓ Essential NetTools (www.tamos.com/products/nettools) for a wide
variety of network scanning functionality
✓ NetScanTools Pro (www.netscantools.com) for dozens of network
security assessment functions, including ping sweeps, port scanning,
and SMTP relay testing