February 2002
Intermediate to advanced
190 pages
4h 56m
English
Content preview from Hardening Cisco RoutersBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 2. IOS Version Security
The first item to discuss when talking about router security is the router’s operating system (OS). The OS on Cisco routers is called Internetworking Operating System, or IOS. Most routers will be running an IOS version between 11.x and 12.x. By the time this book is published, Cisco may have released 13.x. Every OS has vulnerabilities, and IOS is no exception. These vulnerabilities generally allow an attacker to disable a router (a denial of service attack), collect information from a router (information leakage), or reconfigure a router (an actual compromise).
The Need for a Current IOS
A key aspect of every good security plan involves operating system security. Every operating system connected to the Internet is subject to attack. Hackers look for OS vulnerabilities to exploit. Cisco IOS has come under increasing scrutiny over the past few years. Bugtraq, a full disclosure vulnerability forum, reports 14 Cisco vulnerabilities between 1992 and 1999, 23 in 2000, and 42 in 2001. Once posted on Bugtraq, these vulnerabilities are seen by thousands of hackers a day and are used in numerous attacks. With such an increase in vulnerabilities, secure routers must have a current and stable version of IOS. The next section on IOS versions provides information on how to identify secure IOS releases.
Determining the IOS Version
You must know what IOS version your routers are currently running before determining whether you should use the latest release. To determine ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.