I read the Snort Cookbook because I am always trying to learn more about Snort. I've read almost every book on the open source intrusion detection system, so I hoped the Snort Cookbook might offer advice not found elsewhere. Unfortunately, whatever good material appears in the book is overshadowed by outdated or outright bad advice. The best Snort book is still Syngress' Snort 2.1, so I recommend reading that title.
The Snort Cookbook starts poorly with ch 1, which at 50 pages is the book's largest. After repeating installation instructions covered in online resources, the book turns to dubious packet collection recommendations. Item 1.10 suggests creating a listen-only Ethernet cable but never mentions disabling ARP traffic with ifconfig's -arp option. Item 1.11 describes how to build a homebrew tap but doesn't address signal regeneration problems that could result in traffic loss.
Item 1.12 gives terrible advice: "If your Snort machine has only one network interface, using the passive tap, run both lines to a small hub. Then from another port of the hub, run a cable to your IDS. This will combine and maybe even buffer the traffic for the IDS and give a full duplex connection." Wrong -- this is a nice way to never see traffic when full-duplex packets from the two transmit lines collide in the hub.
Item 1.14 says "Snort itself is incapable of sniffing a wireless network," but it ignores the fact that while Snort doesn't understand 802.11 traffic, the sensor can join a wireless network and interpret what it sees. Item 1.15 demonstrates more ignorance of hardware issues by saying "Linux-compatible gigabit Ethernet cards are available with up to six ports. Coupled with machines that have space for three or four PCI cards, you could have as many as 24 Ethernet ports." This suggestion completely ignores the fact that a single gigabit NIC will saturate a 32 bit, 33 MHz PCI bus, and many BIOS will not be able to handle interrupts from more than about 8 NICs in a PC.
Item 1.25 says "two to four million records is the max for MySQL," which is odd. One MySQL database I use to collect session data on Sguil has over 31 million records. Item 1.25 also covers the often-repeated and incredibly naive method of having Snort log directly to a database, without utilizing Barnyard as an intermediary. Thankfully we see Barnyard covered in ch 2, but recommended for "high-speed network[s], such as 1 Gbps or greater." Barnyard is definitely appropriate when monitoring at less than gigabit speeds.
Throughout the book, the obsolete ACID Web-based alert console appears. BASE has been available since October 2004; it addresses stale code problems in ACID and should have been covered. I was disappointed to see the Sguil suite mentioned but never given any discussion, even though the older Snort 2.1 book introduces using Sguil. Item 4.2 mentions "RST scans" even though they are a fiction of one security researcher's imagination. Item 6.6 claims to offer ways to test Snort by showing three programs (Snot, Sneeze, Stick) that have had little effect on modern Snort implementations (e.g., 2001 on).
On the positive side, in many cases the Snort Cookbook properly addresses questions which frequently appear on the snort-users mailing list. Items 2.15 and 2.16 show how to send Snort alerts to email, a pager, or cell phone using Syslog and Swatch. Item 3.2 discusses rule updates with Oinkmaster. Rule issues in ch 3 were generally helpful, like dynamic rules (3.4), evasion issues (3.10), optimization (3.13), and even Spade (3.18). Perfmon coverage in items 4.6 and 7.0 help discover how well Snort is working. I also liked the policy-based IDS ideas in item 7.5.
The back cover of the Snort Cookbook says the book "can save you countless hours of sifting through dubious online advice or wordy tutorials." That online advice is frequently more correct than what appears in this book. While some of the book is helpful, often that material has already been introduced in online documentation or best covered in Syngress' Snort 2.1. Perhaps a second edition will address the concerns in this review and produce a more useful cookbook for future readers.