Malware - Fighting Malicious Code

AMuse writes "After taking a course at SANS from Ed Skoudis (and later hacking with him at the DefCon "Capture the Flag" contest in Las Vegas), I decided it was time to buy a copy of his latest book and see if he writes as well as he teaches. "Malware: Fighting Malicious code" is his most recent computer security book and was definitely a worthy purchase. Though the topic itself is not for novices, Skoudis does a splendid job of reviewing the basics with each chapter so that a less experienced security professional can follow along and learn. Additionally, he is very careful to show both Windows and UNIX/Linux examples of the topics, making the book accessible to a far wider crowd than some platform centric books I've read." Read on for the rest of AMuse's review. Malware: Fighting Malicious Code author Ed Skoudis pages 636 publisher Prentice Hall rating 9 reviewer Matt Linton ISBN 0131014056 summary A detailed look at malicious computer code, how to examine and defend against it.

One of the finest points of the book is that it's structured with the simplest (and most common) cyber-attacks in the initial chapters, and later in the book builds upon those concepts clearly. With each new chapter he delves deeper into the computer attack world and the increasing complexity of attacks and how to recognize, detect and counter them. Every description of an attack is paired with useful graphics and examples of code dumps or program output. As a bonus, the programs he recommends as tools in his book are the very ones he uses in his demonstrations.

Viruses, Worms and Mobile Code: The first few chapters start out relatively light for an experienced security person. They cover viruses, worms and mobile code (the nifty high level languages like ActiveX, JavaScript and VB which are so easy to abuse). Though the information is on a light level for the pro, a novice would find these chapters packed with useful information and examples of each of many types of nasty code. After each example, the book shows how to recognize an infection, then how to prevent them in the first place.

Trojans and Backdoors Once he's gotten the reader's feet feet wet, Skoudis begins to wade in deeper with discussion and analysis of Trojans and Backdoors. Even a pro will likely read something here that they didn't know before. As a quick example, he covers "port knocking" with spoofed hosts and sniffers as a means of evading detection of your backdoor by pesky net admins. Although these chapters include many high level concepts, Skoudis clearly demonstrates them via real world examples and references to code that you can obtain yourself and try out (On a well isolated network, of course!)

User and Kernel mode Rootkits After a healthy dose of trojans and backdoors, the book moves on to discuss in very great detail the current status of User and Kernel mode rootkits. In my opinion, these two chapters were the most detailed and thorough in the book. All told, about 160 pages of the book are dedicated to the Windows and UNIX/Linux kernels, how they operate and of course how they can be completely taken over and replaced by an attacker. If there's any book that can leave SysAdmins awake at night in paranoid fits, this is the book and these are the chapters.

The truly nasty stuff In the final chapters, he leaves the world of attacks that are already in the wild and discusses attacks that are yet to come. These topics include polymorphic code that alters itself with each infection to evade IDS and Antivirus signatures, tightly packaged combo attacks, potential BIOS rootkits and even microcode attacks where the CPU itself is infected with an attackers' code, hiding rootkits as soon as the power switch is flipped on.

Tying it all together The book then ends with two very helpful chapters which detail how to establish a test lab for yourself and analyze malicious code on your own. As a bonus, there's also a chapter on real world scenarios that you can investigate yourself to see what you've learned.

Conclusion All told, I would recommend this book for any serious security professional or SysAdmin/NetAdmin. It's also a very good read for Novice geeks but, although Skoudis does an excellent job of explaining the basics, the later chapters may be a bit too complex for someone without at least a bit of time as a power user.

You can purchase Malware: Fighting Malicious Code from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page

Comments

Hate to ask...

[Anonymous Coward]

When can we expect Malware: Fighting Ignorant Users? Not trying to troll, this should be step 1 in the battle.

Re:Hate to ask...

[javatips]

Maybe "Malware: Educating Ignorant Users" would be better.

Windows and Linux examples, yes

[ChiralSoftware]

Of course there is malware for Windows and Linux because both are written in unsafe languages which manipulate memory directly and often cast objects to (void *) and use containers (pointers to regions of memory) which don't know their own size. I know I've posted on this before here on /., but as long as we use those tools, we're going to have those problems. It's interesting that he doesn't have any examples of Java malware, for instance.

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Create a WAP server

Re:Windows and Linux examples, yes

[wandazulu]

You sound hungry, so I'll step up.

You might feel safe in thinking that Java's sandbox protects from this kind of thing, but don't be too sure...what is a JVM written in? Those very unsafe languages you talk about.

The fact is, at some point, *somebody's* gotta manipulate the memory directly; somebody's gotta keep track of what's been alloc'ed and what's been free'd, and whether that's at an application level, or at the OS level, you're going to find the very languages that you deem as unsafe.

Abstract away and bytecode your way to a false sense of security, and you've done nothing but put up another curtain to lull you into a false sense of security. The fact is, this kind of thing is *always* going to be with us, whether intentional or by accident (Microsoft's whole KB).

Think of it this way: cars are too dangerous for people to use because there's no way to stop them from running into the ditch. So we're going to develop a system by which everyone's car runs on rails, with all the latest safety systems to make sure everything is safe and secure and drive the way we think they should drive. Now you don't have to trust your own abilities, just us. And we know what's right, right?

Java malware

[heironymouscoward]

Using "safe" languages just displaces the problem.

For example, the obnoxious CoolWebSearch trojan gets into computers via a hole in the MSIE Java runtime.

Further, the number of infections caused by code weaknesses is probably far less than the number caused by social weaknesses - "Click on me!"

Re:Hate to ask...; What about legal remedies?

[David Hume]

When can we expect Malware: Fighting Ignorant Users? Not trying to troll, this should be step 1 in the battle.

In addition, what about legal remedies? It appears that many people legally "agree" to the installation of various forms of malware by mindlessly clicking through on licensing agreements. While consumer education is one possible solution, changing the law of contract might provide another solution. Obviously, these solutions are not mutually exclusive.

Many contracts are, by either statute or common law, void as a matter of public policy. This is one possible solution.

Other contracts (e.g., in the areas of consumer credit, mortgages, etc.) have required language or other provisions.

In other areas (e.g., limitations of liability, waiver of implied warranties, and again consumer credit, mortgages, etc.) there are requirements reqarding the use of clear and understandable language, prominent disclosures and even the size of the type face.

To my knowledge, none of the above possible remedies have been enacted re: click through agreements.

Another recommendation for the book

[Occams Razor]

Like the rest of you, I've read a number of really dry, really dull technical books simply because I needed to know the material they cover. This is the first technical book I've read in a very long time that was actually _fun_ to read. Ed is an excellent author and speaker and the result is that he makes this an entertaining read. I have found myself reading this book just for the fun of it, not purely for the (excellent) technical content.
I have actually put this on the must-read list for anyone doing incident handling for my employer. I can't recommend it highly enough