Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Submission + - Book Review Metasploit (oreilly.com)

eldavojohn writes: "The Metasploit Framework has come a long way and currently allows just about anyone to configure and execute exploits effortlessly. The Penetration Tester's Guide takes current documentation further and provides a valuable resource for people who are interested in security but don't have the time or money to take a training class on Metasploit. The highlights of the book rest on the examples provided to the reader as exercises in exploiting several older versions of operating systems like Windows XP and Ubuntu while at the same time avoiding triggering antivirus or detection. The only weak point of this book is that a couple chapters refer the reader to external texts (on stacks and registers) in order to meet requirements for crafting exploits. The book also gives the reader a brief warning on ethics as many of these exploits and techniques would most likely work on many sites and networks. If you're wondering how seemingly inexperienced groups like lulzsec constantly claim victims, this would be an excellent read.

In 2007, Metasploit was migrated from Perl to Ruby. The book opens with a brief history of the framework and mentions this but does not address any complaints of performance loss. Instead, the authors argues that this increased contributions and adoptions. As a result, all the code in this book (which the exception of some SQL payloads) is written in Ruby. If you don't know Ruby but you know many other languages, it's a fairly simple language to pick up.

The first chapter of this book clearly indicates that the objective is to empower white hat hackers and researchers. They lay down a predefined set of phases that one takes while pen testing a target. They are Pre-engagement Interactions, Intelligence Gathering, Threat Modeling, Vulnerability Analysis, Exploitation, Post Exploitation and Reporting. Chapter two covers the terminology that is used across the Metasploit Framework so if you're unfamiliar with concepts like 'shellcode' or 'payload' this chapter will set you straight. It also mentions a UI for Metasploit called Armitrage but my personal tastes kept me using the minimal MSFConsole and MSFcli.

Chapter three begins to cover intelligence gathering and covers everything from the basic whois tool to writing your own custom scanner. The chapter does a great job of carefully explaining in detail the difference between passive and active scanning. The stealth TCP scan that nmap provides was a new thing for me and the chapter also details how Metasploit can use several database technologies to record and store the results of your scans to be used later on. The chapter shows how to use Metasploit to scan ports, server message blocks, MS SQL servers, SSH servers, FTP and simple network management protocol sweeping. Most of these techniques are a few quick commands in Metasploit's console and with Ruby mixins the chapter illustrates how to write your own scanner for use in Metasploit in about 20 lines of code. But all of this is just to get a grasp of what's up and running on the server.

Chapter four starts to get interesting with actual vulnerability scanning. Banner grabbing is an important technique in pen testing and the book suggests using NeXpose community edition (also a Rapid7 tool). This is covered in more detail in the appendix but NeXpose is a web GUI interface for scanning, storing and managing site scans. This provides great reporting features, it's intuitive and reduces everything to point-and-click for the user. But luckily this tool can also be run from the console (something I preferred). The chapter also covers another popular scanner called Nessus and shows to import the results to Metasploit for use. The chapter also includes noisy options like SMB login scanning or just looking for open VNC or X11 servers. Mentioned here first (but also frequently later in the book) is Back|Track for connecting to such targets. Something neat about this chapter is that if you don't care that your target knows you're attacking them, you can just move from these results collected with NeXpose, Nessus or OpenVAS and drop them into the 'autopwn' tool in Metasploit. It's three commands on the console and apparently works more often than it should.

Chapter five familiarizes the reader with the MSFConsole and its basic commands like showing all the exploits, payloads and targets available in the Metasploit Framework installed. These are constantly updated and maintained so they often change. With that information, the chapter proceeds to step the reader through an exploit in a Windows XP SP2 (MS08-067) and then a Samba exploit in Ubuntu 9.04.

Chapter six spices things up by introducing Meterpreter that extends the Metasploit Framework to serve a shell to the exploited system and from there perform additional attacks. The chapter shows how to brute force an MS SQL server and use the stored procedure xp_cmdshell to gain remote access. Meterpreter has a lot of neat features like keystroke logging, capturing screenshots and dumping password hashes (including the pass-the-hash technique). Simple commands in meterpreter can allow the user to easily and effortlessly accomplish many things: privilege escalation, token impersonation, pivoting to another system, process migration, killing antivirus software, system scraping, the list goes on. The chapter finishes by briefly mentioning an intriguing tool called Railgun that I wish they had spent more time on.

Chapter seven covers avoiding antivirus detection through tools like msfencode (to avoid your exploit being fingerprinted). Even better is encoding it many many times. If you know what antivirus your target uses, you can simply run the antivirus on your encoded exploit on your local machine to see if it's picked up. The chapter also covers the basics on continuing normal execution of a backdoored executable and packers that compress an executable for you with decompression code built in.

The book gets progressively more technical with chapter eight focusing on client side attacks. The chapter covers the NOP slide technique and also introduces the Immunity Debugger. It covers the Internet Explorer Aurora Exploit (MS10.002) as an end of chapter exercise for the reader to do. Chapter nine takes a quite look at Metasploit's auxiliary modules that allow the user to do many other things than just exploits. They run through the source of a mischievous Foursquare Location Poster that can make you appear to be everywhere on Foursquare. They also cover heap spraying attacks in web browsers — a topic that was particularly discomforting for me considering how long I often leave my browser open for.

Chapter ten was probably one of the more boring for me but a very important tool for pen testers. It shows how to turn the Metasploit Framework into a social exploitation tool that can be used to send templated e-mails to distribution lists. The intent of this, of course, is to get one user in a large company to click on a site that looks like their company's homepage and perhaps enter their credentials. By just selecting from lists of options, you can create java applet exploits that appear to be legitimately signed, clone a website like gmail and harvest credentials, tabnabbing, webjacking, man-left-in-the-middle and finally mixing those all together in a multipronged attack. The next chapter is just more exploits via Fast-Track (an open source Python based tool that builds on top of Metasploit).

Chapter twelve covers Karmetasploit, a Metasploit implementaiton of the wireless security tool Karma. The strategy of this exploit is to present your machine as a wireless access point. When a user connects, you can use karmetasploit to host fake webpages and grab their credentials or even gain shell access through a client side attack. Knowing how frequently people attach to anything in coffee shops and airports, this sort of attack could be particularly brutal and extremely easy to execute given Metasploit's simplicity for users.

The final chapters do an okay job of showing you how to first build your own module for Metasploit in chapter thirteen. Then in fourteen, the book looks at building your own exploit and goes into detail about fuzzing applications on your local machine and using the Immunity Debugger to look at what's happening given the fuzzed input. What follows is a lengthy discussion of the Structured Exception Handler (SEH) and the Next SEH (NSEH) and how you can manipulate registers and utilize JMPs to hit a NOP slide into your shellcode. This is one of the longest and most complicated chapters with probably the most technically intensive writing. I would like to see further editions of this book expand on things like this as it was important for me as a software developer to understand how these attacks are manufactured.

Chapter fifteen was similar to fourteen but showed how to port exploits to the metasploit framework. This chapter covers more so the general guidelines for writing exploits for the metasploit framework and doing it so that you leverage metasploit's flexibility. Chapter sixteen covers the scripting abilities of meterpreter and customizing that to execute further exploits once you have access to a target machine with meterpreter.

The final chapter brings the key steps together for a simulated penetration testing of a preconfigured system with web server (the book lists the Pirate Bay as a source of this torrent). As you work through this chapter, the phases of pen testing are exercised with all the aforementioned strategies employed.

This book was a real eye opener to read for a software developer. I haven't done formal pen testing aside from testing my own code so a lot of these advanced concepts were new to me. I enjoyed how the code was laid out with circled numbers marking code (instead of every line being numbered) that were referenced later in the text. I hope future editions of this book provide progressively more and more material as there's clearly a lot of sections that are condensed into a few paragraphs but could be expanded upon almost endlessly. I'm glad this sort of tool didn't exist during my younger more mischievous years as this book demonstrates that it could be used for gaining access to just about anything (depending on how much free time and skill you have).

You can find Metasploit The Penetration Tester's Guide from No Starch Press on Amazon or in digital formats on O'Reilly's site."

This discussion was created for logged-in users only, but now has been archived. No new comments can be posted.

Book Review Metasploit

Comments Filter:

"Everyone's head is a cheap movie show." -- Jeff G. Bone