Archive for October, 2008
Mastering the Windows Registry
PCWizKid has demonstrated how to hack and tweak your registry settings for optimizing your Windows configuration. Now lets take a look on how the registry is setup to better give you an understanding on what you are doing when you edit the registry ne…
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AVG Free Basic Edition v8 provides free antivirus protection for Windows Vista/XP/2000. Installing only 50Mb of files the AVG Free Edition is the smallest antivirus scanner PCWizKid has tested and may well be the best choice for an older PC with limit…
All About SAM Files
What is SAM?
SAM is short for Security Accounts Manager, which is located on the PDC and has information on all user accounts and passwords. Most of the time while the PDC is running, it is being accessed or used.
What do I do with a copy of SAM?
You get passwords. First use a copy of SAMDUMP.EXE to extract the user info out of it. You do not need to import this data into the Registry of your home machine to play with it. You can simply load it up into one of the many applications for cracking passwords, such as L0phtCrack, which is available from: http://www.L0phtCrack.com
Of interest to hackers is the fact that all access control and assorted parameters are located in the Registry. The Registry contains thousands of individual items of data, and is grouped together into “keys” or some type of optional value. These keys are grouped together into subtrees — placing like keys together and making copies of others into separate trees for more convenient system access.
The Registry is divided into four separate subtrees. These subtrees are called
- HKEY_CLASSES_ROOT
- HKEY_CURRENT_USER
- HKEY_LOCAL_MACHINE
- HKEY_USERS
We’ll go through them from most important to the hacker to least important to the hacker.
First and foremost is the HKEY_LOCAL_MACHINE subtree. It contains five different keys. These keys are as follows:
- SAM and SECURITY - These keys contain the info such as user rights, user and group info for the domain (or workgroup if there is no domain), and passwords. In the NT hacker game of capture the flag, this is the flag. Bag this and all bets are off.
The keys are binary data only (for security reasons) and are typically not accessible unless you are an Administrator or in the Administrators group. It is easier to copy the data and play with it offline than to work on directly.
- HARDWARE - this is a storage database of throw-away data that describes the hardware components of the computer. Device drivers and applications build this database during boot and update it during runtime (although most of the database is updated during the boot process). When the computer is rebooted, the data is built again from scratch. It is not recommended to directly edit this particular database unless you can read hex easily.
There are three subkeys under HARDWARE, these are the Description key, the DeviceMap key, and the ResourceMap key. The Description key has describes each hardware resource, the DeviceMap key has data in it specific to individual groups of drivers, and the ResourceMap key tells which driver goes with which resource.
- SYSTEM - This key contains basic operating stuff like what happens at startup, what device drivers are loaded, what services are in use, etc. These are split into ControlSets which have unique system configurations (some bootable, some not), with each ControlSet containing service data and OS components for that ControlSet. Ever had to boot from the “Last Known Good” configuration because something got hosed? That is a ControlSet stored here.
- SOFTWARE - This key has info on software loaded locally. File associations, OLE info, and some miscellaneous configuration data is located here.
The second most important main key is HKEY_USERS. It contains a subkey for each local user who accesses the system, either locally or remotely. If the server is a part of a domain and logs in across the network, their subkey is not stored here, but on a Domain Controller. Things such as Desktop settings and user profiles are stored here.
The third and fourth main keys, HKEY_CURRENT_USER and HKEY_CLASSES_ROOT, contain copies of portions of HKEY_USERS and HKEY_LOCAL_MACHINE respectively. HKEY_CURRENT_USER contains exactly would you would expect a copy of the subkey from HKEY_USERS of the currently logged in user. HKEY_CLASSES_ROOT contains a part of HKEY_LOCAL_MACHINE, specifically from the SOFTWARE subkey. File associations, OLE configuration and dependency information.
What are hives?
Hives are the major subdivisions of all of these subtrees, keys, subkeys, and values that make up the Registry. They contain “related” data.
All hives are stored in %systemroot%\SYSTEM32\CONFIG. The major hives and their files are as follows:
|
Hive |
File |
Backup File |
|
HKEY_LOCAL_MACHINE\SOFTWARE |
SOFTWARE |
SOFTWARE.LOG |
|
HKEY_LOCAL_MACHINE\SECURITY |
SECURITY |
SECURITY.LOG |
|
HKEY_LOCAL_MACHINE\SYSTEM |
SYSTEM |
SYSTEM.LOG |
|
HKEY_LOCAL_MACHINE\SAM |
SAM |
SAM.LOG |
|
HKEY_CURRENT_USER |
USERxxx |
USERxxx.LOG |
|
HKEY_USERS\.DEFAULT |
DEFAULT |
DEFAULT.LOG |
Hackers should look for the SAM file, with the SAM.LOG file as a secondary target. This contains the password info.
|
Hive |
File |
Backup File |
|
HKEY_LOCAL_MACHINE\SOFTWARE |
SOFTWARE |
SOFTWARE.LOG |
|
HKEY_LOCAL_MACHINE\SECURITY |
SECURITY |
SECURITY.LOG |
|
HKEY_LOCAL_MACHINE\SYSTEM |
SYSTEM |
SYSTEM.LOG |
|
HKEY_LOCAL_MACHINE\SAM |
SAM |
SAM.LOG |
|
HKEY_CURRENT_USER |
USERxxx |
USERxxx.LOG |
|
HKEY_USERS\.DEFAULT |
DEFAULT |
DEFAULT.LOG |
Hackers should look for the SAM file, with the SAM.LOG file as a secondary target. This contains the password info.
For ease of use, the Registry is divided into five separate structures that represent the Registry database in its entirety. These five groups are known as Keys, and are discussed below:
HKEY_CURRENT_USER
This registry key contains the configuration information for the user that is currently logged in. The users folders, screen colors, and control panel settings are stored here. This information is known as a User Profile.
HKEY_USERS
In windowsNT 3.5x, user profiles were stored locally (by default) in the systemroot\system32\config directory. In NT4.0, they are stored in the systemroot\profiles directory. User-Specific information is kept there, as well as common, system wide user information.
This change in storage location has been brought about to parallel the way in which Windows95 handles its user profiles. In earlier releases of NT, the user profile was stored as a single file - either locally in the \config directory or centrally on a server. In windowsNT 4, the single user profile has been broken up into a number of subdirectories located below the \profiles directory. The reason for this is mainly due to the way in which the Win95 and WinNT4 operating systems use the underlying directory structure to form part of their new user interface.
HKEY_LOCAL_MACHINE
This key contains configuration information particular to the computer. This information is stored in the systemroot\system32\config directory as persistent operating system files, with the exception of the volatile hardware key.
The information gleaned from this configuration data is used by applications, device drivers, and the WindowsNT 4 operating system. The latter usage determines what system configuration data to use, without respect to the user currently logged on. For this reason the HKEY_LOCAL_MACHINE regsitry key is of specific importance to administrators who want to support and troubleshoot NT 4.
HKEY_LOCAL_MACHINE is probably the most important key in the registry and it contains five subkeys:
- Hardware: Database that describes the physical hardware in the computer, the way device drivers use that hardware, and mappings and related data that link kernel-mode drivers with various user-mode code. All data in this sub-tree is re-created everytime the system is started.
- SAM: The security accounts manager. Security information for user and group accounts and for the domains in NT 4 server.
- Security: Database that contains the local security policy, such as specific user rights. This key is used only by the NT 4 security subsystem.
- Software: Pre-computer software database. This key contains data about software installed on the local computer, as well as configuration information.
- System: Database that controls system start-up, device driver loading, NT 4 services and OS behavior.
Information about the HKEY_LOCAL_MACHINE\SAM Key
This subtree contains the user and group accounts in the SAM database for the local computer. For a computer that is running NT 4, this subtree also contains security information for the domain. The information contained within the SAM registry key is what appears in the user interface of the User Manager utility, as well as in the lists of users and groups that appear when you make use of the Security menu commands in NT4 explorer.
Information about the HKEY_LOCAL_MACHINE\Security key
This subtree contains security information for the local computer. This includes aspects such as assigning user rights, establishing password policies, and the membership of local groups, which are configurable in User Manager.
HKEY_CLASSES_ROOT
The information stored here is used to open the correct application when a file is opened by using Explorer and for Object Linking and Embedding. It is actually a window that reflects information from the HKEY_LOCAL_MACHINE\Software subkey.
HKEY_CURRENT_CONFIG
The information contained in this key is to configure settings such as the software and device drivers to load or the display resolution to use. This key has a software and system subkeys, which keep track of configuration information.
Understanding Hives
The registry is divided into parts called hives. These hives are mapped to a single file and a .LOG file. These files are in the systemroot\system32\config directory.
|
Registry Hive |
File Name |
|
HKEY_LOCAL_MACHINE\SAM |
SAM and SAM.LOG |
|
HKEY_LOCAL_MACHINE\SECURITY |
Security and Security.LOG |
|
HKEY_LOCAL_MACHINE\SOFTWARE |
Software and Software.LOG |
|
HKEY_LOCAL_MACHINE\SYSTEM |
System and System.ALT |
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Remapping Alt and Windows keys on a Mac using Bootcamp
One of my pet peeves with Bootcamp, Apple’s software for letting you run Windows on
a Mac, is that the default keymapping for Apple keyboards swaps the Alt and Windows
keys.
This totally messed with my shortcuts.
I tried using one of my favorite scripting tools, AutoHotKey,
to remap the keys but this ended up being flakey. I also didn’t like the idea of relying
on a running application to do the swapping.
I ran into a program called SharpKeys that
remaps the keys at the OS level. It’s a remarkable little program. You can configure
how you want your keys remmaped and then it writes those changes to the registry.
This ensures that all users of the computer have remapped keys and that the remapped
keys work on non-user space like the Logon prompt.
To remap Alt to Windows you need to:
- Get SharpKeys (download)
- Create a mapping for Left Alt –> Left Windows
- Create a mapping for Left Windows –> Left Alt
- Logoff
Enjoy!
The posts on this weblog are provided “AS IS” with no warranties, and confer no rights. The opinions expressed herein are my own personal opinions and do not represent my employer’s view in any way.
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