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

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124
votes
3answers
22k 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 ...
95
votes
17answers
15k 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 ...
68
votes
13answers
21k 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?
40
votes
6answers
17k 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 ...
74
votes
4answers
12k 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 ...
79
votes
8answers
11k 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 can'...
14
votes
3answers
22k 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 ...
26
votes
5answers
4k 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 ...
28
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 ...
13
votes
6answers
3k 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 ...
47
votes
8answers
6k views

Why is HTTPS not the default protocol?

Why is HTTP still commonly used, instead what I would believe much more secure HTTPS?
157
votes
8answers
74k 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?
33
votes
7answers
3k 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. ...
15
votes
4answers
8k 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 ...
8
votes
5answers
3k views

What are potential security risks when using an insecure wireless connection?

If someone is using an insecure wireless connection (for example a hot spot in a coffee shop) does it pose a threat even if the person is using a secure application layer protocol? What I mean by ...
12
votes
3answers
4k 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 ...
31
votes
2answers
4k 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?
23
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.
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 ...
63
votes
16answers
50k views

What tools are available to assess the security of a web application?

What tools are available to assess the security of a web application? Please provide a small description of what the tool does. Update: More specifically, I'm looking for tools that assume no ...
24
votes
2answers
5k 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 ...
24
votes
5answers
7k 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?
50
votes
5answers
11k 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, non-...
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 ...
64
votes
12answers
14k 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 ...
27
votes
5answers
23k 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 ...
4
votes
4answers
700 views

Why self-signed https is less trustworthy than unencrypted http?

It wouldn't be far-fetched to guesstimate that at least 50% of the web traffic can be intercepted in 2014. However, a guesstimate of active interception attacks is likely an order of magnitude lower&...
72
votes
4answers
27k 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 ...
15
votes
6answers
5k 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 ...
44
votes
6answers
10k 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 (let'...
22
votes
2answers
8k 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?
39
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 ...
31
votes
5answers
6k 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 ...
13
votes
6answers
2k views

Securely building a local pentest lab in a VM

I'd like to set up OWASP WebGoat or a similar vulnerable web app in a VM (probably VirtualBox on Linux). For convenience's sake, I'd like to get it running on one of the primary machines I use (say, a ...
11
votes
3answers
5k views

Must login and logout action have CSRF protection?

I am making a web application in Django which generates and includes CSRF tokens for sessions (a Django session can be anonymous or a registered user). Should I keep CSRF protection to the controllers ...
8
votes
5answers
14k 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 ...
69
votes
2answers
36k 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?
41
votes
15answers
8k views

Should we protect web application source code from being stolen by web hosts through obfuscation?

Is it worth to obfuscate a java web app source code so that the web host cannot make wrong use of the code or even steal your business? If so, how should this be dealt with? How should we obfuscate? ...
4
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?
20
votes
14answers
3k 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 ...
15
votes
3answers
15k 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 ...
14
votes
6answers
3k 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 action....
9
votes
3answers
3k views

Encrypting user data using password and forgot my password

I am planning to do a web application which stores a lot of personal stuff (info, photos...). And to give users a sense of protection, I want to encrypt the data before storing it to the database. So,...
4
votes
2answers
8k 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 ...
23
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 ...
4
votes
3answers
2k 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 ...
11
votes
3answers
3k 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 ...
7
votes
4answers
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 ...
3
votes
3answers
903 views

Flash ignores Content-Type header, allowing XSS?

I recently read that the Flash plugin ignores the Content-Type header in certain circumstances. In particular, you can give Flash a URL, and the Flash plugin will happily fetch the content at that ...
23
votes
4answers
12k views

avoid hitting DB to authenticate a user on EVERY request in stateless web app architecture?

Summary Once a user logs into a web site and his username/password credentials are verified and an active session is established, is it possible to avoid hitting the DB for each and every request ...