ASP.NET Web.config question - asp.net

The server is IIS7.
Is there a way to disable web.config files in subfolders?
I am asking because, I have a folder on the web server that is for uploads. When someone uploads files, a new folder is created for the user's session and the files they upload go in the folder.
So the path to uploads would be like this:
~/uploads/3F2504E0-4F89-11D3-9A0C-0305E82C3301/somefile.txt
In the ~/uploads/ directory there is a web.config file that removes all http handlers except the static file handler and adds a wildcard mime type. So every file that a user uploads will only ever be served statically.
If a user uploads a web.config file, I want to disallow any of the settings in that file from being applied.
How can I do this?
EDIT
Could I just make the upload folder an application that is a member of an application pool configured to run in Classic mode instead of Integrated Pipeline mode? That way it wouldn't even care about a web.config file.
EDIT 2
Is there another type of webserver I could install for serving all files statically? I could just access the files through a different port. Is there some software that I can be sure wont run any scripts and is safe.

I simply wouldn't allow them to upload a file with that name. In fact, I normally wouldn't trust any filename that the user gave me... makes a great candidate for an injection-style attack.

Ok I have a different angle on this...
What if your uploads folder was not part of the website and instead part of the file system? This way ASP.NET is not processing requests to the folder and thus web.config wouldn't be loaded by the ASP.NET runtime.
You'd have to give your app pool's account read/write access to the file system where these files are stored, but I think it better fits what you're trying to accomplish.

Obviously it could be done in code.
If the folders always exist, you could pre-populate with a web.config with no (significant) content and an ACL to ensure it cannot be overwritten, but looking at the path it I suspect you create the upload folders dynamically which means this would not work.

I don't believe there is a way to tell IIS not to use a web.config (but I could be wrong). Personally, I would add a check to my save code and rename the file.

Why not just check the filename first to prevent the user from uploading a file named web.config? You're probably going to want to check for other things too before allowing the upload - files that are too big, etc.

Related

Prevent Direct Access To files ASP Web.Config

Strange question but hopefully its possible.
we have files in the root of our site (/files) these are uploaded through the main cms side of the website (/admin) and to be accessed by people who have access to the (/school) directory.
At the moment, if you have the direct link URL EDIT TO THE FILE you can gain access to the file
the files folder has its own web.config file with some rules, is there a way i can add some of my own authentication within the web.config to only allow requests that come from the School folder to have access to the files?
In my head i would have a piece of VB code that does something like this:
If (Request.UrlReferrer <> Nothing) Then
If Page.Request.UrlReferrer.ToString.Contains("/School/") = True Then
???
End If
Else
Response.Redirect("index.aspx")
End If
I've tested this in a simple page and it seems to work okay.
Well, I would assume that the users who can use school folder are memembers of a secuirty role called School (or some such).
thus, any user not a member of school can't use the pages (or files) in the school folder.
Since you want the SAME restricitons for the folder files, then use the same web.config to secure the files folder.
That will mean only users who can use the shools folders will also be the same group of people that only use the files folder.
Now the above will not stop members of securty role "school" from typing in any valid URL to the files folder. So, if you want to prevent this, then I would suggest that for all files up-loaded, you create a folder inside of files folder based on their PK row in the membership table (Memebership.ProviderKey).
Then what you would do is turn off all role groups rights to the files folder. I perfer not EVER allowing a direct URL to files.
Remember, only IIS respects the IIS security settings and provider for a web based URL. Code behind is 100% free to load, read, write, use, play with ANY file via code behind. Code behind uses plain jane FULL path names - and those path names and file names used by code behind does NOT care nor use IIS security settings. Only web based URL's dish out by IIS respect and use the IIS security settings you have for the schools folder. So, copy the web.config for schools over to files, and you are done.
But, code behind? it does not care nor use those settings at all.
So, code behind does NOT use nor respect nor care about IIS security settings. IIS role membership ONLY applies to the asp.net pages and web based URL's. But, code behind is a 100% free to get and grab any file on the system - even files outside of the wwwroot path name of the web site.
So, as a 2nd level and better security?
I would not allow ANY URL's to the files folder.
You then display a grid or list of files on the web page, and code behind for the download button can then go read/get the file (you can use TransMitFile to download that file)
So, best approach is to not allow ANY valid URL's to the files folder.
However, for now, since you only want people who can use the schools folder also be the SAME people that can use the files folder? Then just use the same web.config for both folders - only those people with role of "school" will thus have use and rights to the files folder.
From the information you provided, then you don't really need any code changes - only to take the security settings from the school folder web.config, and copy that to the files folder, and you should be done.
Now, it is possible that the schools folder is not secured by using IIS security and roles - but then again, that would a epic face plant and horrible design choice.

Confused on what is the correct procedure on storing passwords in Web.config for Azure deployment

I've had a very frustrating experience on putting an MVC 5 app on Azure. I have been reading the following page: http://www.asp.net/identity/overview/features-api/best-practices-for-deploying-passwords-and-other-sensitive-data-to-aspnet-and-azure
But what I haven't managed to put in my head is the following:
Security Warning: Do not add your secrets .config file to your project or check it into source control. By default, Visual Studio sets the Build Action to Content, which means the file is deployed. For more information see Why don't all of the files in my project folder get deployed? Although you can use any extension for the secrets .config file, it's best to keep it .config, as config files are not served by IIS. Notice also that the AppSettingsSecrets.config file is two directory levels up from the web.config file, so it's completely out of the solution directory. By moving the file out of the solution directory, "git add *" won't add it to your repository.
And:
Security Warning: Unlike the AppSettingsSecrets.config file, the external connection strings file must be in the same directory as the root web.config file, so you'll have to take precautions to ensure you don't check it into your source repository.
The problem is the following: When I upload the Web.config file with the external files without being included I get hit by "The System cannot find the file specified", so for it to go away I must include the .config files defeating the purpose of Microsoft's post.
I really really really do not understand. I have added the connectionStrings and appSetting's keys in Azure's portal. What is the correct and secured way of putting my passwords and secrets online? What am I missing? Is it because I'm running in Debug mode?
According to this:
How can I secure passwords stored inside web.config?
There is nothing to worry about accessing the Web.config file...
But that just defies Microsoft's post.
Thanks.
I find the following technique to be the easiest way to do this.
Instead of putting the deployment values of these settings into the web.config, I keep the test values in there instead. I then put the deployment values into the Application Settings section of the Azure Website via the Azure Portal:
When the website runs, these settings will take precedence over what is in the web.config. This helps me avoid externalized files, allows me to keep sane development configuration that the team can share, and makes deployment very easy.
The best way is to set your secrets in the Connection Strings section of the portal. Any values set there will override values you specify in your web.config file.
This way they are only exposed to people who have admin access over the site itself. Having full access to the source won't even be enough to get the secret values.
More details here

Find the path of browser default downloads folder

how can we find the path of browser default downloads folder in c# / asp.net?
For example I can get the path of user desktop like :
Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
Thanks..
You can't find that out in a web application. It's up to the user to decide which browser to use and how to configure it and where to save downloaded files by default and you have absolutely no way of interfering or even knowing his choices from a web application.
First of all looking at MSDN on Environment.SpecialFolder there is no download folder, and the reason is that this is different for every browser.
http://msdn.microsoft.com/en-us/library/system.environment.specialfolder.aspx
And there have nothing to do with asp.net, if you look it from the server side you just get a directory on nowhere, meaning that this have nothing to do with the web application that run under the pool.
What you can do
You can use the HttpRuntime.AppDomainAppPath and use it to know where your site lives, and there place a "download" directory and use this full path:
HttpRuntime.AppDomainAppPath + "download/"
for download/upload files.

web.config ignoring certain files from requiring authentication

In my asp.net web application, I have a folder in which I have a few html and jpeg files. some of these files do not need a user to login while the others do. How do I exclude the files that are free for view to be displayed without logging in while still maintaining the user to login for viewing other files in the same folder using just the config file. I wasnt able to find something relevant in the config file or maybe I overlooked it. If anyone knows please reply.
Thanks.
I've tried to answer this as well as I can but the sentence:
How do I exclude the files that are free for view to be displayed without logging in while still maintaining the user to login for viewing other files in the same folder using just the config file.
..is a bit confusing!
The files that need to be authenticated are the ones that are handled by the asp.net handler such as .aspx files. jpegs and other static files bypass this so can be viewed without authentication. The handler aspnet_isapi only handles certain files but you can configure it to handle more file extensions (or all files) by configuring extension mappings in IIS.
Personally, I would put all files I wanted to be unprotected in a folder with permissions to allow anyone to view that folder, set the aspnet_isapi handler to handle all files and then protect your other folders according to your application's needs.
Depending on what you want to do (as your question isn't that clear), you may or may not be able to achieve what you want just from the config file but hopefully this answer will give you the information you need to make your own conclusions on that.

ASP.NET: external custom config file in a virtual directory - how to?

I know that there at least two approaches to leverage the web.config file:
using the configSource attribute which was introduced in .NET 2.0 - here is a good blog entry about it.
The file attribute of the appSettings tag which lets you point to an external file with a relative path. Described in the MSDN documentation on the appSettings element.
Now, my problem is that both approaches work well only for physical paths. But I need to address a config file which is in a virtual directory.
Which other method could I use to put my config resources in a virtual directory?
Note: I want to do it this way, because I have multiple instances of my web application on the same server (and that on many servers). To keep deployment easy and clean, I want to keep one directory for all the files (aspx, ascx, images, css, js etc.) and point the web apps in IIS for different customers (=domains, https etc.) to this single directory. In every IIS web I would have a virtual directory called "custom" which points to a different folder for each web.
Update: I'd like to point out that this virtual directory "custom" is not suited to contain an inherited web.config - that web.config would be valid only for the custom folder which doesn't contain aspx/ascx files.
I have the same scenario and after reading you post I realised that asp.net won't let you do this for various security reasons.
Therefore I turned to the OS to find an equivalent to the Linux soft link function which in turn led me to the Junction utility from sysinternals. This can create a directory that is actually any other directory on that volume and asp.net can't tell the difference and so happy loads the config sections that are not actually in a subdirectory of you website. Works for me :)
Virtual Directories can be set as applications, and you can just place another web.config there.
It will inherit any changes from the parent config, and you can add custom settings in it.
I was looking to do the same thing but it did not work, so I decided to do the opposite, as you know the web.config can be inherited, so I pointed IIS to a folder containing the client config (connection string, file path etc) files and the website files i put them on a virtual directory with the rest of the webconfig (where it load dll and other application files needed)
So basically i can use the website files to multple clients and the clients with their own Database connection string and other specific client settings.

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