Computer Forensics

Craig Maloney writes "Many Slashdot readers know how to secure a network, and many know how to determine if a security breach has taken place. Fewer readers, though, would know how to handle a security breach if corporate assets were involved. How would you cooperate with law enforcement when a crime has been committed on a computer?" For more questions, and the rest of Maloney's review of Warren G. Kruse II and Jay G. Heiser's Computer Forensics, read on below. Computer Forensics author Warren G. Kruse II and Jay G. Heiser pages 392 publisher Addison Wesley rating 8/10 reviewer Craig Maloney ISBN 0201707195 summary A good reference for what to do when computer crime happens

How do you get the evidence off of a computer, ensuring that it's capable of withstanding a defense lawyer's scrutiny? Maybe you would just unplug the machine and put it in storage awaiting a detective's arrival, but is that what we should do? What if the evidence is on a production server that can't be simply unplugged and put into storage? What if that evidence is slowly being erased as files are created and deleted on that server? How do you help build the case against a computer criminal? Hopefully you'll never have to worry about computer crime in your home or workplace but if you do have to worry, Computer Forensics will be an asset to your part of the investigation.

Who is this book for? Computer crime isn't simple -- it can range from damage done by simple script kiddies to corporate espionage by disgruntled employees, as well as sophisticated, multi-homed attacks by skilled crackers. Computer Forensics tries hard to cover a lot of these areas. The book includes a chapter dealing with laptop hardware, as well as ones on data hiding and encryption, and further chapters on putting evidence together and dealing with law enforcement. While these topics may be of interest to the Slashdot crowd, Computer Forensics focuses more on broad topics of interest to computer detectives faced with getting up to speed quickly with computer crimes and computer evidence gathering.

Several chapters are downright boring for anyone who has a modicum of computer experience. Finding out where e-mail is stored on Windows and Linux machines, or understanding what a root-kit is and what it does will be pedestrian for many readers. Nestled away between the necessary-but-pedestrian topics, though, are some very useful tools. The authors use netcat with tar to copy files between machines without disturbing the modification times (something I would never have thought to use). Novice users will find a wealth of tools and examples in these chapters. The tools used in the book tend toward open source and free tools, and rely heavily on Linux as the Swiss Army knife for handling file systems and files without disturbing them. Any reader should be able to put together a decent set of tools from this book.

Making it all work

Putting together a good forensic kit is all fine and good, but making sure your evidence holds up to the scrutiny of some high-powered, high-priced defense lawyer is much more important. The last chapter of Computer Forensics gives a brief introduction to the criminal justice system. The authors touch on notifying law enforcement agencies, search warrants, probable cause, interviews, subpoenas, dollar loss guidelines, and testifying as an expert witness, among other legal topics. The appendices of the book have checklists, flowcharts, and an incident report form to aid investigation and evidence gathering. These are invaluable resources for the system administrator of any public machine who needs to deal with law enforcement.

Conclusion Thinking about dealing with courts and law enforcement may not be at the forefront of any administrator's job, but it is a reality any administrator needs to think of and be aware of. Computer Forensics will at least make administrators more aware of what their legal options are, and of the form in which gathered forensic data needs to be presented as evidence. Computer detectives will find a good, if not rudimentary example of what to look for when investigating a computer crime scene. This may not be the most comprehensive book on the subject of computer crime, but it will point you in the right direction to help investigate it should it ever happen to you.

You can purchase Computer Forensics 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

SecurityFocus

[ProfaneBaby]

The security focus mailing list dedicated to forensics is also good lurking, for those interested...

http://archives.neohapsis.com/archives/sf/forensic s/

Forensic Security

[djrok212]

Many financial firms including the one where I work, have instituted internal forensic security policies to help limit corporate liability. In our case, we have caught and successfully prosecuted employees for pornography on corporate assets (including child pornography in one case.)

There are designated employees on the forensic team in each department who are responisble for witnessing the process and documenting the chain of custody for data and items.

We've invested in specific equipment, including network sniffers (other then those used by the network group), hard drive replicators, log books, and materials for collection and storage of evidence.

Everything has a chain of custody and is then turned over to the proper authorities.

As far as the law is concerned since the employee does not have a right or expectation of privacy when working on a corporate asset, everything we take is completely legal. As long as we mantain an effective chain of custody it will likely hold up on court.

Just my two cents. Your mileage may vary.

Cutting Loses

[fembots]

What if the evidence is on a production server that can't be simply unplugged and put into storage?

In my company, once a machine is compromised, it's offline and ghost image taken, no questions asked, even it's a live ecommerce site. You would rather putting up a "Unscheduled Outage" notice than inflicting more damages to the server/data.

It's like a 777 pilot asking if he should make an emergency landing due to a fire alarm, because there are 350 passengers onboard and we don't want to spoil their holiday.

Actually I think pilots do that, that's why we get to read blackbox transcript like

GPWS: "Whoop, whoop. Pull up. Whoop whoop. Pull up."
CA: "Don't worry we can make it."
GPWS: "Whoop, whoop. Pull -."

Been there, done that.

[rylin]

Recently, I was contacted by the local PD in regards to a huge number of stolen CCs being used from our IP-range (Internet Café).
After getting a list of specific timestamps (along with IP-addresses), I was able to figure out who the culprit was.
That said, the man-hours I put into the whole thing seem to have been for nothing.
The PD won't do jack shit - too little resources, they say - which is why I find it funny that they can't even send a unit to pick up the frauders when they're actually on-site (yet they can be seen parading the streets, looking for minors consuming alcohol).

Just because law enforcement want your help doesn't mean they'll do anything - even if you virtually hand them the crooks on a silver platter.
Then again, things might be different elsewhere.

outdated?

[Boolio]

The publication date on the book linked is 2001. That makes this book three to four years old. While some of the information may be the same, there are quite a number of new tools and techniques out there. So some of this may be pretty outdated. I have yet to find a great book on system forensics. The best so far is the book "Know Your Enemy" buy contributors to the HoneyNey Project.

This is dangerous stuff to mess around with...

[Pacifix]

... like security, forensics is best left to those who really know what they're doing. The results of a forensics investigation can very often end up being part of a civil or criminal case and amature mistakes can get the case thrown out. Contaminating the data by not properly imaging it, not knowing where to find hidden data, or misinterpreting what is found are all very easy to do. Be very sure you have all your bases covered before selling yourself as a forensic investigator.