2KKUU7ita

228
Part IV: Hacking Operating Systems
more features, or uneducated users, but there seems to be a lot more that
can happen in a Windows environment. That said, Linux is certainly not flawless.
In addition to the password attacks I cover in Chapter 7, certain remote
and local attacks are possible against Linux-based systems. In this chapter,
I show you some security issues in the Linux operating system and outline
some countermeasures to plug the holes so you can keep the bad guys out.
Don’t let the title of this chapter fool you — a lot of this information applies
to all flavors of UNIX.
Understanding Linux Vulnerabilities
Vulnerabilities and attacks against Linux are creating business risks in a
growing number of organizations — especially e-commerce companies, network
and security product vendors, and ISPs that rely on Linux for many
of their systems. When Linux systems are hacked, the victim organizations
can experience the same side effects as their Windows-using counterparts,
including:
✓ Leakage of sensitive information
✓ Cracked passwords
✓ Corrupted or deleted databases
✓ Systems taken completely offline
Choosing Tools
You can use many UNIX-based security tools to test your Linux systems.
Some are much better than others. I often find that my Windows-based commercial
tools do as good a job as any. My favorites are as follows:
✓ BackTrack Linux (www.backtrack-linux.org) toolset on a bootable
CD or .iso image file
✓ LanGuard (www.gfi.com/network-security-vulnerabilityscanner)
for port scanning, OS enumeration, and vulnerability testing
✓ NetScanTools Pro (www.netscantools.com) for port scanning, OS
enumeration, and much more
✓ Nmap (http://nmap.org) for OS fingerprinting and detailed port
scanning
✓ QualysGuard (www.qualys.com) for OS fingerprinting, port scanning,
and very detailed and accurate vulnerability testing