An application that is accessed over a network such as the Internet or an intranet using a browser.

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81
votes
17answers
13k views

Does an established SSL connection mean a line is really secure?

From the view of somebody offering a web application, when somebody connects with SSL (https) to our service and submits the correct authentication data, is it safe to transmit all sensitive data over ...
64
votes
13answers
17k views

What are the pros and cons of site wide SSL (https)?

What are the pros and cons of encrypting all HTTP traffic for the whole site through SSL, as opposed to SSL on just the login page?
92
votes
3answers
16k views

Is a rand from /dev/urandom secure for a login key?

Lets say I want to create a cookie for a user. Would simply generating a 1024 bit string by using /dev/urandom, and checking if it already exists (looping until I get a unique one) suffice? Or should ...
69
votes
4answers
10k views

Can anybody explain XSS? [closed]

I work programming Enterprise Java applications and do very little web development in 2002. I'm interested in security and like to read articles about it. However, I never fully understand how XSS ...
75
votes
8answers
9k views

Can anyone provide references for implementing web application self password reset mechanisms properly?

We are implementing self password reset on a web application, and I know how I want to do it (email time limited password reset URL to users pre-registered email address). My problem is that I ...
14
votes
3answers
14k views

Why does Hydra return 16 valid passwords when none are valid?

I've been playing around with Hydra and DVWA and I've hit a bit of a snag - Hydra responds letting me know that the first 16 passwords in my password list are correct when none of them are. I assume ...
23
votes
5answers
3k views

Security of an initial redirection from http://example.com to https://example.com

Suppose that http://example.com/<foo> systematically redirects to https://example.com/<foo>. I enter http://example.com in my browser's URL bar, and I see a page load and the URL bar now ...
25
votes
1answer
3k views

What cookie attacks are possible between computers in related DNS domains (*.example.com)?

Here, several servers in the same DNS domain emit cookies under a variety of settings (scope, HTTPS, Secure) and another host emits a cookie with the same value. Example Suppose a user has the ...
9
votes
6answers
2k views

Filter user input before the database or upon display?

Given a web application where user data must be properly escaped to avoid XSS, is it better to try to remove the "bad stuff" before it enters the database, or is it best to allow it in the database ...
43
votes
8answers
5k views

Why is HTTPS not the default protocol?

Why is HTTP still commonly used, instead what I would believe much more secure HTTPS?
21
votes
7answers
1k views

How can I protect a WordPress installation?

How do you go about protecting a default WordPress installation? What checklist do you use, best practices, tips and tricks, etc? Any recommendations on plugins, third-party tools are welcome.
117
votes
8answers
50k views

Is BASIC-Auth secure if done over HTTPS?

I'm making a REST-API and it's straight forward to do BASIC auth login. Then let HTTPS secure the connection so the password is protected when the api is used. Can this be considered secure?
26
votes
2answers
3k views

How can a Software application defend against DoS or DDoS?

Most of the solutions for DoS attacks are not at the application level. In case I am using a proxy server, what are the possible countermeasures for DoS at the application level?
13
votes
4answers
4k views

How to protect against login CSRF?

http://seclab.stanford.edu/websec/csrf/csrf.pdf points out that most CSRF protection mechanisms fail to protect login forms. As http://stackoverflow.com/a/15350123/14731 explains: The ...
23
votes
5answers
17k views

What is the correct way to implement anti-CSRF form tokens?

I am fully aware of CSRF and have already implemented some safe forms, but I have never been happy with the results yet. I've created tokens as a md5 of username, form info and a salt and stored it ...
11
votes
3answers
3k 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 ...
15
votes
4answers
1k 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 ...
20
votes
2answers
4k views

Guidance for implementors of HTTPS-only sites (Server side)

The recent trend in HTTPS attacks is to attack the HTTP protocol. What should I do to increase my site's security if the only protocol I want is HTTPS? Some easy to implement ideas are Implement ...
21
votes
5answers
5k 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?
32
votes
7answers
2k views

Is there a difference between GET and POST for web application security?

I have 2 choices in sending data between 2 web applications. I encode the data in Base64 and append to the URL and retrieve these parameters at my destination application and decode the parameters. ...
18
votes
5answers
1k views

Can you secure a web app from FireSheep without using SSL?

Assume that you want to give some web users privileged access to your website, but that you are unable (or unwilling) to offer SSL to all of them - at least past the initial login page. In this ...
5
votes
1answer
59k views

Chrome is telling me I am receiving a forged certificate for Gmail, is someone trying to hack me?

I went to log on to https://mail.google.com this morning and I got the following error. Is someone trying to attack me or is this just a bug? I'm on a WPA2 encrypted wireless connection using Chrome ...
20
votes
14answers
2k views

How can you become a competent web application security expert without breaking the law?

This question was asked here on Programmers Exchange, but it was suggested I ask here as well since most of the experts would likely hang out on IT Security exchange instead. I find this to be ...
29
votes
4answers
10k views

https security - should password be hashed server-side or client-side?

I am building a web application which requires users to login. All communication goes through https. I am using bcrypt to hash passwords. I am facing a dilemma - I used to think it is safer to make a ...
12
votes
6answers
4k views

How do I get started with security? (beginner) [closed]

I have been working in web development for a fair amount of time. I am looking at developing in either Python (Django etc.) or PHP. I am new to security. Where do I begin looking? What are basic ...
41
votes
5answers
8k views

How to Securely Implement a “Remember Me” Feature?

Assuming you already have a website that implements all of the standard login stuff, what is the correct and most secure way to allow users to automatically be logged in for a certain time period ...
22
votes
3answers
7k views

What are the best practices for hardening a php.ini file?

In order to secure a PHP installation, what are the best settings for a php.ini file? What is absolutely vital in terms of security? What is recommended for most use cases?
35
votes
8answers
3k views

If I include a Forgot Password service, then what's the point of using a password?

I've implemented a Forgot Password service in the following way: User goes to login page, clicks on "Forgot password?" User is presented with a form that asks for their email address. Email is sent ...
30
votes
5answers
5k views

Could mint.com be more secure, and if so, how?

After reading a bit about mint.com on the money stack exchange, I wanted to give it a try. But frankly, it scares me a little bit. The site has a bunch of links explaining how they're so secure. I ...
55
votes
12answers
11k views

What to do about websites that store plain text passwords

I recently received an email from a popular graduate job web site (prospects.ac.uk) that I haven't used in a while suggesting I use a new feature. It contained both my username and password in plain ...
7
votes
5answers
11k views

Hiding JavaScript source code

In a web-app should one strive to hide as much of the code as possible, for example from view source? In particular I was wondering should JavaScript be hidden, especially ones used for Ajax? I was ...
17
votes
3answers
3k views

Should I have a maximum password length?

I'm creating a webapp, and part of my authentication method is password length. Should I put one in place? (say, 50 characters?) Or should I just put a minimum length (Currently at 6). Are there ...
7
votes
3answers
2k views

Is a mobile app more secure for mobile use than the “normal” website?

An untrained end user who uses a mobile web browser is vulnerable to phishing and can't easily verify the the authenticity (or security) of a website among other issues. Also, it is very easy to ...
54
votes
4answers
17k views

Why is the same origin policy so important?

I can't really fully understand what same origin domain means. I know it means that when getting a resource from another domain (say a JS file) it will run from the context of the domain that serves ...
55
votes
2answers
25k views

ssltest: Chain issues - Contains anchor

I've run ssltest on web application and it found "Chain issues - Contains anchor" (section "Additional Certificates (if supplied)") What does it mean? Should it be fixed? Can it be exploited?
11
votes
3answers
12k 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 ...
10
votes
3answers
14k views

Is it possible to execute a php script in an image file? [duplicate]

I have an image upload php website. Users can upload images to my website. A user claims he can hack my website using an uploaded image. I opened all the images that he uploaded to my server with ...
7
votes
4answers
918 views

Security attacks on PHP web applications

I know about following security attacks on php applications (html,php,js). XSS SQL Injection CSFR Session Hijacking /Fixation Code Injection Remote file injection Should i know about any other or ...
19
votes
2answers
3k views

Which HTTP status codes are interesting from a security point of view?

I'm looking to extract interesting information from webserver logs and I wonder which HTTP status codes should I filter out? For example, 200 hits can be considered to be 'regular behavior' whereas ...
13
votes
6answers
2k views

How secure is redirecting user from http://normal.bank.com to https://secure.bank.com?

I have an application. Which works on http, http://normal.bank.com. But for log-in, performing any action, etc. I am rediecting user to https://secure.bank.com, where user can login and perform ...
4
votes
2answers
6k views

HTML encoding to protect against XSS

While going through some references about protection against XSS i found that it is a good practice to encode data (entered by users) before using it to generate a dynamic page. I was not able to find ...
3
votes
3answers
636 views

External cross domain include script

One of my web application underwent a vulnerability assessment recently, and one of the findings is about cross domain include script. Our web app uses addthis_widget.js from AddThis to bookmark ...
3
votes
4answers
1k views

Can a CSRF CAPTCHA be defeated?

One defense that developers use to protect against a CSRF attack is to implement a CAPTCHA in critical steps. A CAPTCHA ensures that a human is at the keyboard approving the activity. But I've ...
9
votes
3answers
2k 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 ...
121
votes
2answers
77k views

What is the difference between https://google.com and https://encrypted.google.com?

Is it there any difference between the encrypted Google search (at https://encrypted.google.com) and the ordinary HTTPS Google search (at https://google.com)? In terms of security what were the ...
5
votes
2answers
817 views

Beginners materials for web security [duplicate]

Possible Duplicate: Resources to learn about security What materials can I study to learn web development security. I'm a web developer, I use ASP.NET, Java, PHP, and JavaScript. I want to ...
3
votes
6answers
3k views

Best resources to learn web security attacks? [closed]

Can anyone suggest good resources to learn about vulnerabilities in and attacks on web sites, in a hands-on way, for someone with limited programming experience?
39
votes
5answers
8k views

Are GUIDs safe for one-time tokens?

I see a lot of sites use GUIDs for password resets, unsubscribe requests and other forms of unique identification. Presumably they are appealing because they are easy to generate, unique, ...
26
votes
2answers
4k views

How do I use Markdown securely?

How do I use the Markdown library safely? What do I need to do to make sure that its output is safe to include into my web page? I want to allow untrusted users to enter content (in Markdown ...
25
votes
9answers
2k views

Why do some people really hate security via client-side?

For instance, lets look at a common login system for a website HTTPS connection is made User submits credentials via POST Server-side code hashes the password and looks if it matches the user name ...