APCO 2P11 Lab 9


In this lab you will focus on learning the roll the windows registry plays. You will look at the components of the registry and learn how to manually edit it.

Introduction & Startup (5 min)

Set up your Dell machines and boot into windows.

Exercise 1 (25 Min)

The windows registry is a database used by windows to hold configuration settings from everything to an installed application down to individual user preferences. Rather then repeat what has already been written, go to wikipedia [http://en.wikipedia.org/wiki/Windows_registry] and read up on the registry. Don't do any modifications yet, that will come. When you are finished reading, answer the following questions.

What is the windows registry?

What is a key?

What are the 5 main registry classes and their associated abbreviation?

What tool do you use to gain access to the registry?

Exercise 2 (30 Min) (Registry Backup)

Playing around with the registry can cause severe problems to arise if you are not careful. It is important to learn how to back up the registry or system state prior to making any changes. At worst, if things don't work out, you can restore the previous version. There are a variety of ways to say the system state. Let us go through a few.

Backing up the Win 7 Registry

Method 1: Using System Restore

One way to backup the registry is to create a System Restore snapshot. System Restore returns your computer to a previous snapshot without losing recent personal information, such as documents, history lists, favourites, or e-mail. It monitors the computer and many applications for changes and creates restore points. You restore these snapshots when your configuration isn't working. This method is unreliable in case you want to rollback the registry changes made a longtime ago, in which case the System Restore might have purged that particular restore point - due to space constraints or due to a recent system restore point or even a Restore point corruption. Please remember, System Restore points get deleted for many reasons, making it unreliable, especially in the long run.

How do I create a System Restore point?

Click Start, right click Computer -> properties

On the left, select System Protection

At the bottom is a button Create...

1) Try creating a system restore point.

Method 2: Backing up the selected branch of the registry by exporting (Reliable)

This method is preferred if you're making changes to a specific key/area of the registry. To backup a selected branch/key in the registry, try this:

REGISTRY1.JPG (37886 bytes)    REGISTRY2.JPG (41671 bytes)
(Backing up a selected branch/key of the registry)

Now that you've created a Registry backup for that particular key. Save the REG file in a safer location in case you want to undo the registry changes made. You can restore the settings by just double-clicking the REG file. It automatically merges the contents to the Registry.

2) Open regedit.  Using the above method make a backup copy of the following key. Save the backup somewhere safe, for the purpose of the exercise put it in the windows temp directory. Call the file desktop.

    HKEY_CURRENT_USER\Control Panel\Desktop

What benefit does a hive file have over a reg file?

For practice, create a hive file of the above key.

Method 2 (a) : Export registry keys using a command-line (Console Registry Tool)

You can use the Console Registry Tool for Windows (Reg.exe) to edit the registry. For help with the Reg.exe tool, type reg /? at the Command Prompt.

4)  Open a command window, see accessories, cmd.

type reg /?, one of the options is to query a specific registry key.

Try to query HKEY_CURRENT_USER\Control Panel\Desktop, note: if the key has any spaces in it, like this one does, you will need to enclose the entire key in double quotes "".

Example: To export the key [ HKEY_CURRENT_USER\Control Panel\Desktop] and it's sub-keys, try this from Command Prompt:

REG EXPORT  "HKEY_CURRENT_USER\Control Panel\Desktop" C:\desk.REG

To view the REG contents type notepad C:\desk.reg in Start, Run dialog. Console Registry Tool is extremely handy for network admins and also for home users.

Method 3: Backing up the whole registry ("System state")

For backing up the whole registry, use the NTBackup utility to back up the System State. The System State includes the registry, the COM+ Class Registration Database, and your boot files. See section "Back Up the Whole Registry" in the following article:
We won't be doing this. Instead lets take a look at some third party software. From the APCO 2P11 software folder ,  install Erunt. It will say for XP and NT but works fine with win7.

After you install and run the software, goto the Windows/Erdnt directory. Notice that the backup includes all parts of the registry, including an NTuser.dat for each user login on the machine. These are exact images of the registry files. Should things go bad, then a restore will put set the registry back to the saved state.

Exercise 3 (30 min.) (Lets Play!)

As you might of guessed by now, Windows has a registry editor called RegEdit. In fact there are many such editing tools available, mostly third party. For our purposes, we will use RegEdit. You can start RegEdit from Start - Run.

When you have made a change to the registry, the effects may not be immediate. In cases where a user key is changed, you must log out and in again for the effect to be realized. When making changes to the local machine or system keys, a reboot may be required.

There are many hacks which you can use. Google "registry, blah blah blah", each of the following. In most cases microsoft will supply the required information.

Show your lab instructor after each registry hack.

Exercise 4 (20 min.)

Ever wonder why all those system try icons start every time you start windows. Or why that application always starts when you log in. The windows registry has a verity of keys which will run applications on startup and log in. In most cases you want these to run, for example antivirus software should start, where as some malware like spyware will start applications and run in the back ground doing what they are best at, spying. The result of a rather nasty piece of malware prompted me to discover HiJackThis. This application scans the registry for any keys which instruct programs to start executing on startup. These keys may come from system files, registry or startup files. Download HiJackThis from the resource section.

For a complete list of Hjt entries refer to [http://www.malwarehelp.org/understanding-and-interpreting-hjt1.html]. This is quite useful when determining why your machine is doing funky things. Caution: Hjt will list all programs which run on startup. Some of these are required for your machine to run smoothly. Do not arbitrarily delete entries until you verify what they do.

Some of the more useful keys are F0, F1 and O4, These are often attacked by Malware.

Run HiJackThis (Hjt).  What programs are listed as startup items from F0, F1 and O4.

Something which will do much the same thing is msconfig. Type this in on Start - Run. Notice the registry keys which are listed. Select only of these programs, and do a search using regedit to locate the key. Do not delete it.

Open msconfig, are the same programs listed in startup? They likely are.

Exercise 5 (20 min) Events and Services

From Control Panel - Administrative tools, start the services console.

Windows services are (daemon) programs which run in the background and provide a necessary service. Some of these are started when the OS comes to life at startup. For example, locate the "Automatic Updates" service. This service allows your computer to automatically download Windows Updates and apply them. Can you disable this service?

You can temporarily stop this service, do so--- then re-enable it. Note that if a service fails, you can specify options to restart the service, what options are these?

If anything on the machine fails or a significant event has taken place, it is recorded in the event log. You can access the event log by using event view. The event viewer can be accessed from Administrative tool. What are the 3 main classes of events? Describe what each is for.

Now lets see what was stopped and started again. The automatic updates would be a system event. What time was the service disabled? What time was it enabled?

Who was the last person to log into this machine and when?

Which events are recorded, are determined by the user and system security policies. These can be changed by editing the "Local Computer Policy". For example, to determine who has had success or failure logging into your machine, you would turn on the Audit logon events (provided they are not already enabled). The policy editor is accessible from administrative tools. You will want to edit the Local Policies and navigate to Audit Policy, turn on Audit account log in events to monitor failures.

Exercise 6 (15 min) (Registry Cleaning)

Why should I clean my registry? [http://onecare.live.com/site/en-us/article/registry_cleaner_why.htm]

Over time, the Windows Registry can begin to contain information that's no longer valid. Maybe you uninstalled an application without using the Add or Remove Programs function in the Control Panel, or perhaps an object or file in the registry got moved. Eventually this orphaned or misplaced information accumulates and begins to clog your registry, potentially slowing down your PC and causing error messages and system crashes. You might also notice that your PC's startup process is slower than it used to be. Cleaning your registry is the easiest way to help avoid these common problems.

Install Eusing Registry Cleaner from the resource folder. Run this software. It should identify a number of keys which have become outdated. It is important to not just trust that software such as Eusing will delete all the right things. Before doing any registry cleaning, ensure you saved a restore point or have backed up the registry. Also, review any deletions which the software recommends.

Exercise 7 ( 15 min) (BSODs)

BSOD or Blue Screen of Death is a typical response when hardware goes bad or a driver becomes corrupt/missing/ or outdated. Once a BSOD happens when windows is running, a mini-dump file is created to help diagnose the problem. These dump files can be accessed by some third party software.

To start, lets cause windows to crash. Start the task manager Ctrl+Alt+Del, and "Show processes from all users". Locate a process called csrss.exe. There may be 2 of them, kill the larger of the 2. Windows will crash!!!!!!  Restart Windows.

From the resource folder, install Blue Screen View. Start the application and inspect the latest crash. The dump in this case may not directly implicate the cause, but it does give a good starting point. You may find other dump files present depending how many times you have crashed your machine.