Nov 13, 2015 01:01 pm | Aseem Kishore | Windows XP
Configure or Turn Off DEP (Data Execution Prevention) in Windows
Data Execution Prevention, otherwise known as DEP, is a set of technologies incorporated into Windows XP SP2 and later that prevents code from being run in certain regions of memory that are not authorized.
This helps to prevent all kinds of attacks and exploits, that normally would be able to run freely, from executing. Data Execution Prevention comes in two flavors, hardware-enforced DEP and software-enforced DEP.
Most users will never need to worry about DEP because it works in the background and normally only protects Windows system binaries or programs that "opt-in". However, if DEP is turned on for all programs, it can cause issues with certain programs.
DEP will sometimes shut down a program or process without any notification if it violates DEP. Normally, these are third-party or older programs not written properly for Windows.
You can turn off Data Execution Prevention for a particular program in Windows by following the steps below. Note that you can turn off DEP globally for the entire system, but it's not recommended as it makes your computer less secure.
Enable/Disbable DEP
Step 1: Right-click on My Computer and choose Properties. Then click on the Advanced tab and then Settings under Performance.
In Windows 8 or Windows 10, you right-click on This PC, choose Properties and then click on the Advanced system settings link.
Step 2: Now click on the Data Execution Prevention tab and you'll see two radio buttons:
Step 3: Here is where it can be a bit tricky. By default, DEP should be set to the first radio button and therefore only protect essential Windows programs and services. If the second radio button is selected, it will turn on DEP for ALL processes, not just Windows processes.
If you’re having issues with a program, go ahead and try to select the first radio button, restart your computer and see if that fixes the issue. If not, you can go ahead and click the Turn on DEP for all programs and services except those I select button and then add the program that is having problems. Make sure to check the box also.
However, DEP is now turned on for every other program in Windows and you might end up having the same problem with other programs. In that case, you have to manually each program to the exception list.
Step 4: Click the Add button and browse to the location of the executable for the program you want to remove from DEP protection.
It’s also worth noting that you might get an error message stating You can not set DEP attributes on 64-bit executables when adding a 64-bit executable to the exception list. This is OK because it means that your computer is 64-bit and that your processor already supports hardware-based DEP.
This means that all 64-bit processes are always protected. The only way to prevent DEP from protecting a 64-bit application is to turn it off completely. However, in order to turn off DEP completely, you have to use the command line.
Turn DEP Always On/Always Off
In addition to the two settings you see in the Data Execution Prevention tab above, there are two more settings you can configure for DEP.
Always On - DEP will be on for all processes in Window and you cannot exempt any process or program from protection
Always Off - DEP will be completely turned off and no process or program, including Windows processes, will be protected.
To do this, open the command prompt by clicking on Start, typing in CMD, right-clicking on the first item and choosing Run as administrator.
Now to turn DEP to always on, copy and paste the following command:
bcdedit.exe /set {current} nx AlwaysOn
To always turn off DEP, type the following command:
bcdedit.exe /set {current} nx AlwaysOff
Note that you only need to run one of these commands, not both like shown above. You’ll also need to restart your computer after any change you make to DEP.
Once you have made the changes, you’ll notice that the Windows interface for changing DEP settings has been disabled, so only use the command line options if necessary. One option gives you absolutely no protection and one gives you complete protection.
The default and ideal option is to have the first radio button checked, which will only protect essential Windows programs and services. If you have any questions, feel free to comment. Enjoy!
Nov 13, 2015 11:44 am | Aseem Kishore | Computer Tips
How to Set File and Folder Permissions in Windows
Normally, you don’t have to worry about permissions in Windows because that’s already taken care of by the operating system. Each user has their own profile and their own set of permissions, which prevents unauthorized access to files and folders.
There are times, however, when you might want to manually configure the permissions on a set of files or folders in order to prevent other users from accessing the data. This post is assuming the other “people” also have access to the same computer you are using.
If not, you may as well just encrypt your hard drive and that’s it. However, when others can access the computer, like family or friends, then permissions can come in handy.
The only other occasion where you will need to mess around with folder or file permissions is when you get a Permission Denied error when trying to access data. This means you can take ownership of files that don’t belong to your current user account and still access them.
This is important because it means that setting permissions on a file or folder does not guarantee the security of that file or folder. In Windows, an administrator on any Windows PC can override the permissions on a set of files and folders by taking ownership of them. Once you have ownership, you can set your own permissions.
So what does this mean in English? Basically, if you have data you don’t want others to see, then you should either not store it on that computer at all or you should use an encryption tool like TrueCrypt.
For those tech-savvy readers, you’ll probably be saying “Hey wait, TrueCrypt has been discontinued due to security vulnerabilities and shouldn’t be used!” Well, that is correct, however, TrueCrypt has been audited by an independent organization and Phase I and Phase II have been completed.
The only version you should download is TrueCrypt 7.1a, the one that has been uploaded to a verified mirror on GitHub. If you are not comfortable at all using TrueCrypt, the only other suggestion I have is VeraCrypt, which was the successor to TrueCrypt, but fixed many of the flaws.
File and Folder Permissions
Now that we got all of that out of the way, let’s talk about permissions in Windows. Every file and every folder in Windows has its own set of permissions. Permissions can be broken down into Access Control Lists with users and their corresponding rights. Here is an example with the user list at the top and the rights at the bottom:
Permissions are also either inherited or not. Normally in Windows, every file or folder gets their permissions from the parent folder. This hierarchy keeps going all the way up to the root of the hard drive. The simplest permissions have at least three users: SYSTEM, currently logged in user account and the Administrators group.
These permissions usually come from the C:\Users\Username folder on your hard drive. You can access these permissions by right-clicking on a file or folder, choosing Properties and then clicking on the Security tab. To edit permissions for a particular user, click on that user and then click the Edit button.
Note that if the permissions are greyed out, like in the example above, the permissions are being inherited from the containing folder. I’ll talk about how you can remove inherited permissions further below, but first let’s understand the different types of permissions.
Permission Types
There are basically six types of permissions in Windows: Full Control, Modify, Read & Execute, List Folder Contents, Read, and Write. List Folder Contents is the only permission that is exclusive to folders. There are more advanced attributes, but you’ll never need to worry about those.
So what do each of these permissions mean? Well, here is a nice chart from Microsoft’s website that breaks on what each permissions means for files and for folders:
Now that you understand what each permission controls, let’s take a look at modifying some permissions and checking out the results.
Editing Permissions
Before you can edit any permissions, you have to have ownership of the file or folder. If the owner is another user account or a system account like Local System or TrustedInstaller, you won’t be able to edit the permissions.
If you set Full Control permissions on a folder for a user, the user will be able to delete any file or subfolder regardless of what permissions are set for those files or subfolders.
By default permissions are inherited, so if you want custom permissions for a file or folder, you have to first disable inheritance.
Deny permissions override Allow permissions, so use them sparingly and preferably only on specific users, not groups
If you right-click on a file or folder, choose Properties and click on the Security tab, we can now try to edit some permissions. Go ahead and click the Edit button to get started.
At this point, there are a couple of things you can do. Firstly, you’ll notice that the Allow column is probably greyed out and can’t be edited. This is because of the inheritance I was talking about earlier.
However, you can check items on the Deny column. So if you just want to block access to a folder for a specific user or group, click the Add button first and once added, you can check the Deny button next to Full Control.
When you click the Add button, you have to type in the user name or group name into the box and then click on Check Names to make sure it’s correct. If you don’t remember the user or group name, click on the Advanced button and then just click Find Now. It will show you all the users and groups.
Click OK and the user or group will be added to the access control list. Now you can check the Allow column or Deny column. As mentioned, try to use Deny only for users instead of groups.
Now what happens if we try to remove a user or group from the list. Well, you can easily remove the user you just added, but if you try to remove any of the items that were already there, you’ll get an error message.
In order to disable inheritance, you have to go back to the main Security tab for the file or folder and click on the Advanced button at the bottom.
On Windows 7, you’ll one extra tab for Owner. In Windows 10, they just moved that to the top and you have to click Change. Anyway, in Windows 7, click on Change Permissions at the bottom of the first tab.
On the Advanced Security Settings dialog, uncheck the Include inheritable permissions from this object’s parent box.
When you do that, another dialog box will popup and it will ask you whether you want to convert the inherited permissions to explicit permissions or whether you just want to remove all the inherited permissions.
Unless you really know exactly what permissions you want, I suggest choosing Add (explicit permissions) and then just removing whatever you don’t want afterwards. Basically, clicking on Add will keep all the same permissions, but now they won’t be greyed out and you can click Remove to delete any user or group. Clicking Remove, will start you off with a clean slate.
In Windows 10, it looks slightly different. After clicking on the Advanced button, you have to click on Disable Inheritance.
When you click on that button, you’ll get the same options as in Windows 7, but just in a different form. The Convert option is the same as Add and the second option is the same as Remove.
The only thing you have to understand now is the Effective Permissions or Effective Access tab. So what is effective permissions? Well, let’s see the example above. I have a text file and my account, Aseem, has Full Control. Now what if I add another item to the list so that the group Users is denied Full Control.
The only problem here is that the Aseem account is also part of the Users group. So I have Full Control in one permission and Deny in another, which one wins? Well, as I mentioned above, Deny always overrides Allow, so Deny will win, but we can also confirm this manually.
Click on Advanced and go to the Effective Permissionsor Effective Access tab. In Windows 7, click the Select button and type in the user or group name. In Windows 10, click the Select a user link.
In Windows 7, once you select the the user, it will instantly show the permissions in the list box below. As you can see, all of the permissions are unchecked, which makes sense.
In Windows 10, you have to click the View effective access button after selecting the user. You’ll also get a nice red X for no access and a green check mark for allowed access, which is a bit easier to read.
So now you pretty much know all there is to know about Windows file and folder permissions. It does take some playing around yourself in order to get the hang of it all.
The main points to understand are that you need to be the owner in order to edit permissions and that any administrator can take ownership of files and folders regardless of the permissions on those objects. If you have any questions, feel free to post a comment. Enjoy!
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