1
vote
2answers
109 views

I can upload any file to an ASP webapp/IIS server but I do not know where (which folder), is this exploitable?

I'm able to upload any file to an ASP webapp/IIS server. My first though is to upload an ASP shell but I don't know where the file has been uploaded. I have written a Python script that beggining ...
1
vote
1answer
35 views

make specially encoded template available for file uploads

A comment to this blog post at sans.org about secure file uploads suggests making a pre-formatted template available for users when they need to do file uploads. The user would use the template to ...
1
vote
1answer
488 views

File upload vulnerability

I am trying to pentest a webapp challenge. Is the following control code vulnerable to file upload? I would like to upload a php shell... I am able to upload shell.php.jpg file but I receive the ...
1
vote
1answer
190 views

Have I done enough not be compromised through image uploading

I know that you can never be sure that you have done enough to be secure, and I also know that file uploading is hard to make correct. Before asking this question I read some of the related posts here ...
0
votes
3answers
114 views

Regarding Cross-Site Scripting attacks

My application has an Upload Management Module and accepts Excel and text files to our server. I detected invalid data inside some uploaded files (the uploader put ...
2
votes
2answers
455 views

Unrestricted File Upload - Possible exploits

During a penetration test‎ (exercise) on a IIS web server + MYSQL DBMS, I have found an Unrestricted File Upload vulnerability for which I can upload a .php file. So I have tried to upload a php ...
8
votes
3answers
1k views

What is the next step of this file upload attack?

Yesterday I discovered somebody had uploaded this PHP code to my server as a .jpg file via my asp.net MVC application's "Upload your profile picture" form. I believe the attack was unsuccessful for a ...
3
votes
3answers
410 views

is it safe to allow external images to be attached to Blog or any Web content?

I am filtering all images that attached to any content of my blog: Check for file extension. Check content type using $finfo = finfo_open(FILEINFO_MIME_TYPE); I also save the image temporary on my ...
2
votes
1answer
530 views

Methods for uploading shell to a website

I know shells can be uploaded via sql injection, remote file inclusion and exploiting the web app's own upload mechanism. Are there any other ways to upload a shell to a website and be able to execute ...
2
votes
4answers
1k views

Is it necessary to scan users' file uploads by antivirus?

Web application allows users to upload files. Is it necessary to scan those files by antivirus? I'd want to hear answer in two scenarios: Type of file isn't checked when uploading. They are stored ...
2
votes
3answers
429 views

Pentesting file Upload feature

The file(resume) upload feature is accepting any sort of files. I have uploaded the PHP shell into it. How do I again access to that uploaded file? I'm bruteforcing the web directory to check for ...
2
votes
1answer
220 views

Is it safe to invoke PHP GD functions if you don't know whether file is a valid image?

There is image upload function in web application. After image is uploaded, it's resized using functions from PHP GD like imagecopyresampled and others. Before invocation of PHP GD's functions there ...
1
vote
1answer
297 views

What are security risks of serving user uploaded files without Content-Disposition?

Imagine a server that serves untrusted user-provided files and allows other users to download them. Under some circumstances server can be tricked to return responses to download file requests without ...
1
vote
4answers
566 views

Security risks of hosting user-supplied images?

I have a program that will accept and fetch images from urls. It will check if the extension is .png, .jpg, etc... I will fetch these files and store them, they will be shown to users in a gallery ...
7
votes
3answers
4k views

Is it possible to inject HTML into image to provoke XSS?

Some answers mention that it's possible to inject attacker-controlled HTML into images and therefore provoke XSS. I guess that this HTML will be processed by browser only if hole exists in browser. ...
8
votes
3answers
8k views

Does X-Content-Type-Options really prevent content sniffing attacks?

In Tangled Web Michal Zalewski says: Refrain from using Content-Type: application/octet-stream and use application/binary instead, especially for unknown document types. Refrain from returning ...
2
votes
2answers
841 views

Why should crossdomain.xml be present if user-uploaded files exist?

In his book Michal Zalewski says: To protect your users, include a top-level crossdomain.xml file with the permitted-cross-domain-policies parameter set to master-only or by-content-type, even if ...
5
votes
2answers
1k views

Antivirus for scanning anonymous file uploads

Since I have no experience with AV solutions on Unix-like environments, I would need help with suggestions on something that can be suitable for scanning files that are uploaded by anonymous users ...
14
votes
4answers
669 views

Is it safe to store and replay user-provided mime types?

If a user uploads a file but modifies the request by setting the mime-type to something arbitrary, like "superdangerous/blackhatstuff", is it safe for me to send the same mime type back to a different ...
10
votes
3answers
2k views

Using file extension and MIME type (as output by file -i -b) combination to determine unsafe files?

We allow users to upload a number of files, all of which we either send over to scribd (doc, xls, ppts, etc) or display as a video ourselves (flv, mov, mp4, etc in flowplayer). To avoid users ...
5
votes
6answers
980 views

How to defend vs. Image Remote File Inclusion, e.g. RFI using a .gif file (Apache/PHP)?

To defend versus Remote File Inclusion where attackers try to abuse image files, I usually recommend to never use include to include image files into PHP code. Sometimes though, the avoidance of ...
16
votes
3answers
3k views

What are the security risks of letting the users upload content to my site?

As a web designer (not a security expert) I wonder: If I allow users to upload content to my website (videos, images and text files), what are the real risks involved?