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
Related
I've had this question for many years, and did research every time that this issue arose, but could never find a definite answer. Somehow the mighty Internet, MSDN, community forums, are either silent or vague on this. Out of thousands of development-related uncertainties, this is the only one that remained elusive.
To the point: in order to enable users to upload and manage images (and other files) used in their blog posts, in a shared hosting environment, I can either consider SQL Server binary data types (performance implications), or the file system. To use the latter, the necessary permissions need to be set for the IIS_IUSRS role on the storage directory : create/write, read and delete. My question - if I do this, what are the security implications? Could someone somehow take advantage of this, bypass the ASP.NET request pipeline and manipulate the files inside the folder without making a request to the corresponding ASP.NET handler (which checks rights, validates uploads, etc.)?
I've developed several systems that allowed file uploads and this has always bothered me. Now, hopefully, someone will be able to put my mind at ease and, ideally, explain the mechanics behind the process.
UPDATE
After viewing the latest answers (many thanks), another formulation of the question:
Is it in any way possible for a client to somehow bypass the request pipeline and create/delete files inside a directory that allows it (assuming the person knows the directory structure)? Or only the code that handles the request can do it? Any potential exploits?
The main problem is to been able to upload a script, an aspx page, in this directory with the photo files, and runs it.
Here is one case: I've been hacked. Evil aspx file uploaded called AspxSpy. They're still trying. Help me trap them‼
The solution to that is to add this extra web.config file on the directories that allow to upload files and not permit to run any aspx page. Also double check to allow only extensions that you permit and not allow to change that on the file name, if they have the opportunity to make rename.
<configuration>
<system.web>
<authorization>
<deny users="*" />
</authorization>
</system.web>
</configuration>
Also on the directories that you allow to upload files, do not permit to run any other script like simple asp, or php or exe, or anything.
general speaking
All your pages have permissions to run and manipulate many things on the server. What you give now is the ability of write on some directories, also by using some aspx page. The asp.net now have one more extra permission to write files there, on the photo folder. Also note here, that you asp.net page have this control, not the user. What you do there with your code can write on this directories, so must be carefuller there to double check where you write and not allow any other directories, not allow the user to manipulate the directory that can be written to.
So this is the weak link. To been able to upload more script that can take control of the server, at least the part that can be access by the asp.net user of this pool.
Having done this before, I'd make two recommendations:
First, do not store the uploaded files in the same directory structure as your application code (if possible). Make it a well-defined external location, and locked down explicitly to only the user the application is running as. This makes it harder for a malicious upload to be injected into your application as nothing in the web server, or ASP.NET itself, knows how to access the file (only your application).
If that is absolutely not possible to do so, be sure to make sure no external user can access the storage folder using standard ASP.NET authorization and only allow writes by your application user to this folder, nothing else.
Second, do not store the uploaded files with their original names and file extensions; Keep that meta-data separate. Just consider the file a raw binary blob of data. This is good for a couple reasons. First, it prevents inadvertent execution of the file on the server, be it by someone accessing the file system directly, the web server, or ASP.NET. Second, it makes it much more difficult for an attacker to exploit a malicious upload as they should never be able to guess the name, or path, of the file on the server.
I would like to store some meta-information about a given site instance that can (a) be managed by that site instance and (b) persist clobbering of Web.config file.
The site will run in multiple environments (dev,testing,staging and production) and each environment can have different values for this metadata.
Note: All environments are running IIS 7.0+
The Root Web.config seems very appealing, as it is certainly outside of the website. Therefore, both files and databases can be changed while maintaining the metadata. I have seen how to modify the appSettings of the Web.config stored in the website, but is it possible to similarly modify the appSettings in the Root Web.config (Specifically within the proper directive)?
If you have other suggestions of approaching this problem, I would be very happy to hear them. Thank you!
would not use web.config for runtime modifications, that will cause the application to recycle, perhaps some other form of configuration file like app.config
if my assumption is incorrect and the web.config will not be edited after the application is started, then you can use WebConfigurationManager to access the file sections
Yes you can modufy the app settings within your web.config Just use the WebConfigurationManager class in the System.Web.Configuration namespace to create a Configuration object. This object could then be used to read and write changes to the web.config file.
You could then create your own "keys" or attributes that could be read as needed.
Depending upon what your attributes represent or if they need to be picked up by multiple environmnets from that server I would also look into making the modifications within the machine.config file as then those settings would apply to the enter machine and thereby picked up by multiple environments( if you are hosting multiple webapps from the server). This could save you time in modifying multiple web.config files and narrorw the storage or the metadata to one location vs. multiple config files in certain situations.
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.
I have an application with 2 directories (books and export).
If we create a book or a page of a book in the application a directory is added with the id of the page (this is for uploading resources).
If we delete a page, the page (and it's directory) is removed from the database and the filesystem.
However this resulted in a session loss (even an application restart). I've looked up some thing on google and found the following link.
It seems to be a problem in ASP.NET 2.0 (and 3.5).
We are now thinking about writing a service that will clean up the directories at night.
But there has got to be another solution for this no?
Oh and putting the directory outside the virtual directory is not an option.
Try disabling the monitoring of File System. This will prevent your session alive.
This article may be usefull for you.
Oh and putting the directory outside
the virtual directory is not an
option.
Putting the directory outside the virtual directory is the only solution I found (so far). What you can do, is to create a link (junction) in the file system so that the directory appears to be inside the virtual directory, e.g:
Our web site (virtual directory) is located at C:\projectX\website
the data directory (where we create/delete files and folders) is located at C:\projectX\data
then we create a link which makes the data folder available as C:\projectX\website\data
The link is created using the program Linkd.exe (available in the windows resource kit), with the following command:
linkd c:\projectX\website\data c:\projectX\data
Now c:\projectX\website\data is a link/junction which points to the real data directory. You can work with the link as if it were a physical directory.
E.g. in your web site you can access it using this code:
Server.MapPath("~/data")
And you can also used the windows file explorer and browse to C:\projectX\website\data. It appears just like a real directory.
There seems to be a supported hotfix which achieves the same as the article Sachin mentioned (turn off the file change notifications in a web site).
Check this article in the microsoft KB for more information.
But since you mentioned in a comment, that you do not have access to the server, I guess this will also not help in your case.
For storing data files that are frequently updated, created and deleted you need to use App_Data folder in the root of the web site. MSDN for App_Data folder states:
Contains application data files
including MDF files, XML files, as
well as other data store files. The
App_Data folder is used by ASP.NET 2.0
to store an application's local
database, which can be used for
maintaining membership and role
information.
Also check Q&A section for App_Data folder usage: App_Data folder question
I had the same problem. The solution is to externalize the session handling by using the ASP.Net State service. The only draw back is that every object you place in the session needs to be serializable, as it is transferred to the state service and back.
I currently do not have the possibility to provide further links, but google will help you, now that you know what to search for.
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.