I'm using CF9. My problem pertains to an admin application that sets session variables at login to identify the user and user permissions. Depending on the user level, certain pages are allowed for viewing and other pages are not allowed. (I'll refer to this as my 'security framework'. This is wrapped around everything in the root.)
This security framework consists of a cfif statement at the top of the CFM page and a closing cfelse and (</)cfif at the bottom of the page. Everything between this opening cfif and closing cfif displays if the user has that level permission - standard stuff.
Certain users can upload PDF files, no problem here. PDF files are uploaded to a folder outside of the root and then moved and renamed to folders inside the root.
When uploading, the user chooses categories and subcategories etc. and these variables are inserted in a SQL database during the upload process. Therefore, I have filePaths and fileNames, etc. to set up dynamic links on a page for a user to click and load the PDF (password protected) in the browser.
I have the dynamic link pointing to a ShowThisPDF.cfm? with URL variables filePath= #filePath# & fileName = #fileName#. I've set up the ShowThisPDF.cfm with the security framework at the top and bottom of the page and am trying to copy the uploaded PDF into this page so that the PDF will display in the browser.
I've tried many ways to do this with cfdocument and cfpdf and cfcontent, etc. When I read the error that this is throwing, it does look like it is reaching the uploaded file but I get an "access denied" every time, due to the security framework I suppose.
On a side note, elsewhere in this application I can create a PDF from my cf pages with cfdocument with the security framework wrapped around the page and this works perfectly - displaying the PDF in the browser. My problem is in loading an existing PDF into a CFM page that has the security framework - which should allow the PDF to load.
Anyone have an idea as to how I can accomplish the above? I hate to try and bypass my security and it seems logical to "copy" the uploaded PDF into a CFM page that wraps the PDF in the security framework and then display the PDF in the browser.
Agree with Dan - I had similar issue. So I ended up doing https: with a windows login and also a ColdFusion Login to Web Application. At end of day - they need 2 logins to get into the system - then they can see the pdf files etc or what they need.
Related
I have a web application where user can upload and view files. The user has a link next to the file (s)he has uploaded. Clicking on the link will open the file in the browser (if possible) or show the download dialog (of the browser). Meaning that, if the user upload an html/pdf/txt file it will be rendered in the browser but if it is a word document, it will be downloaded.
It is identified that rendering the HTML file in the browser could be a vulnerability - Cross Site Scripting.
What is the right solution to this problem? The two options I am currently looking at are:
to put Content-Disposition header in the response to make HTML files downloaded instead viewed in the browser.
to find some html scrubbing/sanitizing library to remove any javascript from the file before I serve it.
Looking at the gmail, they do the second approach (of scrubbing) with having a separate domain for the file download - may be to minimize/distract the attack surface. However in this approach the receiver gets a different file than what was sent. Which is not 'right' in my opinion; may be I am biased. In my case, the first one is easy to fix. But I wonder if that is enough, or is there any thing that I overlook!
What are your thoughts on these approaches? Or do you have any other suggestions?
Based on your description, I can see 3 posible attack types (maybe there are more):
Client side code execution
As you said, your web server may serve a file as HTML and run javascript code on the client. This can be avoided with Content-Disposition but I would go with MIME types control through Content-Type. I would define my known type of files (e.g. pdf, jpeg etc.) and serve them with their respective MIME type (e.g. application/pdf, image/jpeg etc.). Anything else I would serve it as application/octet-stream.
Server side code execution
Althougth I see this as an out of topic attack (since it involves other parts of your application and your server) be sure to avoid executing files on the server (e.g. PHP code through LFI). Your webserver should not access directly the files (e.g. again PHP), better store them somethere not accesible through a URL and retrive them on request.
Think if here you are able to reject files (e.g. reject .exe uploads) and ask the user to zip them first.
Trust issues
Since the files are under the same domain, the files will be accesible from javascript (ajax or load as script) and other programs (or people) may trust your links. This is also related to the previous point, if you don't need unzipped exe files, don't allow them. Using an other domain may mitigate some trust problems.
Other ideas:
Zip all files uploaded
Scan each file with antivirus software
PS: For me sanitization would not work in your case. The risk of missing something is too high.
I currently have a web app made in node.js. One feature of this app is to take notes. I want to provide the user with a way to browse the internet and select a text to add as a note in our web app without having to manually copy-pasting from one browser window to our app.
I know I can do this relatively simply using a Chrome extension that would be linked to the user account and would save the note to the database. However, I cannot use this approach since not all my users can install Google Chrome.
Therefore, I am looking for a way to browse the web from inside our web app. For example, it could be in an iFrame where we display a complete browser. That way, the user could navigate the web for information from inside the app, select text to save and click on a button (probably located outside the iFrame browser) to save the selected text as a note in our database.
How can I achieve such a thing in node.js ?
This is, essentially, impossible.
For you to get any data about the site the user was browsing you could either:
Restrict them to browsing sites willing to partner with you to give you permission to access their data via postMessage (a technical change on their part to work around the Same Origin Policy)
Proxy every request through your server which would:
Have large bandwidth requirements
Require a lot of rewriting of URLs (including dynamically generated ones in JS)
Require rewriting of X-Frames-Options and Access-Control-Allow-Origin headers
Need users who would trust you with all the data you passed through your system (including their passwords to third party sites)
Not work for Intranet sites (since your server could not reach them)
I want to export a table to an Excel file. I need to export a report.
ORA_EXCEL.new_document;
ORA_EXCEL.add_sheet('Sheet name');
ORA_EXCEL.query_to_sheet('select * from mytable');
ORA_EXCEL.save_to_blob(myblob);
I saved my table to blob.
How do I export/respond to the user (client)?
I need something that is simple to allow a user to be able to download an Excel file to their own computer. I tried doing this procedure in an Oracle workflow:
ORA_EXCEL.save_to_file('EXPORT_DIR', 'example.xlsx');
But this did not help, because it is saves the file to a directory on the server and I need it in the real server.
The way I have handled similar issues in the past was to work with the systems people to mount a directory from either a web server or file server on the Database server.
Then create a directory object so that the procedure can save to a location that is accessible to the user.
If the files are not sensitive and there are a limited number of users then a file server makes sense as it is then just a matter of giving the user access to the file share.
If files are sensitive or this is a large number or unknown users we then used the Web server and sent a email with a link to the user enabling them to download their file. Naturally there needs to be security built into this to stop people being able to download other users files.
We didn't just email the files as an attachment because...
1) Emails with attachments tend to get blocked
2) We always advise not to open attachments on emails. (Yes I know we advise not to click on links as well but nothing is perfect)
Who or what is invoking the production of the document?
If it´s done by an application, which the user is working on, this application can fetch the BLOB, stores it at f.e. TEMP-Directory and calls
System.Diagnostics.Process.Start("..."); to open it with the associated application. (see Open file with associated application)
If it´s a website, this one could stream the blob back as Excel-Mimetype (see Setting mime type for excel document)
Also you could store in an Oracle-DIRECTORY, but this one has to be on the server and should be a netword-share to be accessible for clients (which is rarely accepted in a productive environment!)
If MAIL isn´t the solution, then maybe FTP can be a way to store files in a common share. See UTL_TCP - Package, with this a FTP-transfer can be achieved (a bit hard to code, but there are solutions to find in the web) and I guess, professional tools that generate Office-documents out of Oracle-DB and distribute them do it like this.
I've built an online system that allows users to download PDF files using ColdFusion. Users have to log in before they can download the files (PDF & Microsoft Office documents). (This application is only for our company staff.)
However, only today I found out that anyone with internet access can view the files. With only certain keywords such as 'Medical Form myCompanyName' in a Google search, they can view the PDF files using the browser.
How can I prevent this?
UPDATE
this is what my problem is. i've created a folder for all of the PDFs file. each of the files is called using ID from database. if let's say a user wanted to view Medical Form, the link would be: http://myApplication.myCompanyName/forms.cfm?Department=Account&filesID=001.
if the user copy this url & log out from system, he/she will not be able to view this file.(login page will be displayed)
However, without the url, other internet users sstill can view the pdf files just by search it on the net, and the search engine will gives a link that direct it to the folder itself, without having to login.
Example:
Medical Form's pdf file is stored in a folder named Document. when an internet user search for Medical Form, the search engine will link it to: http://myApplication.myCompanyName/Document/Medical%20Form.pdf
we have lots of PDF files in this folder and most of it are confidential, and for internal view purpose only. in php, we can disable this by using .htaccess. i'd like to know if there's anything like this for coldfusion?
You can send files through the code with single line like this:
<cfif isAuthorized>
<cfcontent file="/path/to/files/outside/of/web/root/Form.pdf" type="application/pdf" reset="true" />
</cfif>
ColdFusion FTW, right.
Please note that handling large files (say, 100MB+) may cause some problems, because files being pushed to RAM before sending. Looks like this is not correct any more, as Mike's answer explains.
Another option is to use content type like x-application if you want to force download.
UPD
You want to put this code into the file (let's say file.cfm) and use it for PDF links. Something like this:
Download file Xyz.pdf
file.cfm:
<!--- with trailing slash --->
<cfset basePath = "/path/to/files/outside/of/web/root/" />
<cfif isAuthorized AND StructKeyExists(url, "filename")
AND FileExists(basePath & url.filename)
AND isFile(basePath & url.filename)
AND GetDirectoryFromPath(basePath & url.filename) EQ basePath>
<cfcontent file="#basePath##url.filename#" type="application/pdf" reset="true" />
<cfelse>
<cfoutput>File not found, or you are not authorized to see it</cfoutput>
</cfif>
UPD2
Added GetDirectoryFromPath(basePath & url.filename) EQ basePath as easy and quick protection from the security issue mentioned.
Personally I usually use ID/database approach, though this answer was initially intended as simple guidance, not really compehensive solution.
You need to store your PDF's outside of your web realm.
So lets say the base of your web app is
/website/www
All http (web) requests are served from there.
/website/pdf
could be a path where all PDF's are stored. This path isn't accessible via URL as its not served by your web server.
Then in www
you have something like
downloadpdf.cfm?file=NameOfPDF.pdf
Which does your checks to ensure its an appropiate user and if so serves the document
<cfcontent type="application/pdf" file="/website/pdf/#url.file#" />
Using cfcontent, pre cf8, is a really bad idea, as it loads the entire file into memory before transmission. CF8 and later will actually stream from disk, which resolves the memory issue. However if you have large files, users on slow connections, and/or heavy downloads you still have to worry about thread starvation. Each download with cfcontent ties up a thread for the duration of the download.
Depending on your web server you might be able to route around this by using an x-sendfile extension. This allows you to send an http header with the path to a file outside of your web root, and have your web server handle sending the file, freeing up cf to do further work.
Here's an article by Ben Nadel about using mod_xsendfile on apache, http://www.bennadel.com/blog/2170-Streaming-Secure-Files-Efficiently-With-ColdFusion-And-MOD-XSendFile.htm and here's an equivalent IIS7 XSendFile plugin https://github.com/stakach/IIS-X-Sendfile-plugin
You might checkout the snippet of code for CFWheels SendFile() helper tag http://cfwheels.org/docs/1-1/function/sendfile
https://gist.github.com/1528113
I'm creating an image gallery site that you have to log in to access. The site will use sessions to keep track of usernames and passwords. Logged in users will be able to search for images and see results. Presumably, this means I'll be putting images in a web directory. How do I keep non-logged in people from being able to browse directly to an image in this directory?
This is PHP-based, with MySQL.
Check for a referrer header, and require it to be from your site.
You can also check that cookies get sent to you (that they're logged in).
Your best bet is then having PHP fetch the images from a location outside of your web dir.
Also, check out the comment string: using mod_rewrite can do all this directly from apache.
Put the images in a folder that isn't accessible through a direct Url, and have the program serve the image directly
Don't put the images in a browsable directory. Better yet, store them outside of your webroot. Put some sort of custom handler in place that will load the requested image and send it back to the user, after the user has been validated and verified. This will also prevent hot-linking of your images.
Put the images in a folder outside the web site, and use a proxy page to send the image to the browser. Make a page that you use as url in your img tag, something like:
getimage.php?id=8783475
In the page you check that the user is logged in, and determine from the parameters what image to send. Set the content type of the page to the type that matches the image, for example "image/jpeg", read the image file and send directly to the response stream.
If your images are not too large, there is a very smart way of protecting them from unauthorized access.
You can you base64 econding, the same as Outlook Express attachment encoding, and put the code inside an ASP page which uses the SESSION object. SEE TUTORIALS ON ASP FOR MORE ON THIS SUBJECT.
When a user accesses the page, the asp code checks if the user is autheticated. If he isn't the script interrupts the page code, not visualizing the image.
If the user is authenticated the scripts loads the entire page and the base64 is reconstructed into a visible image.
The trick here is that you don't have a directory with plain images in it, but the image is encoded in the page html, so it is reconstructed on the fly by the script.
Since you don't have images in the directory, nobody can attempt to point the browser directly to them, since thay simply do not exist.
You can use this site to encode the images:
http://www.motobit.com/util/base64-decoder-encoder.asp
Then you have to "call" the image in the html code using this tag:
img src="data:image/gif;base64, ..............................................(here you place the code obtained from the site above)...............
You're done! Your images are not accessible if the user is not logged in.
Do not let people access your image directories directly.
Let your image gallery software forward the image to the user. Check the needed credentials.