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

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20
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1answer
14k views

What key exchange mechanism should be used in TLS?

There are many key exchange mechanisms that can be used in TLS. Among them are RSA, ECDH_ECDSA, ECDHE_ECDSA, ECDH_RSA, ECDHE_RSA and others. Which of these are more cryptographically secure and can be ...
20
votes
5answers
1k views

Why do some websites and programs restrict password characteristics?

There are some websites and even programs that I use that have rediculous password restrictions. Lots of forums for instance restrict passwords to ~32 characters. Others enforce a restricted charset. ...
20
votes
4answers
11k 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 ...
20
votes
5answers
2k views

Should I use Suhosin for PHP?

Suhosin can be used to increase the security of your php application. I can really see the use of it when you are using shared hosts, with multiple (possibly evil) people running their PHP apps ...
20
votes
7answers
865 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.
20
votes
3answers
6k 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?
19
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 ...
19
votes
2answers
662 views

How is “<scrscriptipt>” or “selselectect” used to avoid filtering?

A technique for avoid filtering of common words is the one I described in the title. However, why does this technique work? SELECT isn't the same as SELSELECTECT for example.
18
votes
6answers
2k views

Why do we ask for a user's existing password when changing their password?

In a web applications context, when a user wants to change their current password, generally they would have to enter their current password first. However at this point, the user has already been ...
18
votes
7answers
2k views

What are some good website security scanning solutions?

What are some good web-based website security scanning solutions? I'm not too concerned if they are web-based solutions, or software that can be run locally. Generally, I'm looking for something we ...
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 ...
18
votes
2answers
2k 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 ...
18
votes
8answers
1k views

How to protect against brute forcing

How do you properly implement defenses against brute forcing? Is it best to store how many times someone tried to log in and block them after X attempts? And how would "someone" be identified? With ...
18
votes
1answer
3k 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 ...
18
votes
4answers
13k views

How to hijack a session?

Despite the blatant title of the question, this is actually for a genuine purpose. My site uses PHP code like this: $select="select id from tableA where user_id='".$_SESSION['sess_user_id']."'"; ...
17
votes
5answers
1k views

From a security standpoint should users be asked to confirm their password when registering?

Is it advisable to have users re-type their password to confirm it's correct? On User Experience the general consensus seems to be no but I'm wondering if this has security ramifications? EDIT: my ...
17
votes
8answers
13k views

Why do people still use/recommend MD5 if it is cracked since 1996?

It's still commonly recommended way of hashing passwords, even if it's insecurity had been proven in 1996 Therefore we suggest that in the future MD5 should no longer be implemented in ...
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 ...
17
votes
4answers
667 views

Should I be concerned when a “Forgot Password?” tool sends my password in plaintext?

Some sites I have been a member of in the past don't go through the normal "Forgot Password?" process. Instead of e-mailing me a unique password reset link or something of the like, I have received ...
17
votes
2answers
2k views

JavaScript Injection using Man in the Middle Attack

Suppose I am connected to a wifi-hotspot hosted by a malicious attacker. Further, suppose that I am accessing a login page of an fictitious email site tmail.com over insecure HTTP connection. My ...
17
votes
5answers
2k 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 ...
17
votes
2answers
605 views

What risks should I be aware of before allowing advertisements being placed on my website?

The thought of having a 3rd party send javascript, and images to end users seems to be a scary thought, but that is exactly what we are doing when I place advertisements onto my site. Does serving ...
17
votes
3answers
4k 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?
17
votes
4answers
2k views

What is the point of the same-domain rule for xmlhttprequest when script tags/JSONP can cross domains?

I get that I don't want a page loaded from stackoverflow.com to be able to request gmail.com on my behalf and read my email--but this seems to be simply a cookie issue. Since JSONP bypasses ...
16
votes
3answers
3k views

Is encrypting SALT with given user's password more secure?

I'm learning about web security. I understand that passwords are hashed with salt. Why aren't the salts encrypted with same user's password? Cloudn't this make password cracking much harder? ...
16
votes
5answers
2k views

Is it possible to inject values in a drop down list?

Say a ASP.NET page, or any html page for that matter, has a drop down list with a bunch of prices. On posting the page, the code looks at the selection of the drop down list for a computation. Is it ...
16
votes
4answers
4k views

Should sensitive data ever be passed in the query string?

Should sensitive data ever be passed via the query string as opposed to the postback? I realize that the query string will be encrypted, but are there other reasons to avoid passing data in the ...
16
votes
3answers
1k views

Is it a vulnerability to display exception messages in an error page?

Our web application has an error page that displays the absolute URL path and query of the page on which the error occurred, the date/time of the error, and the exception message. (We do not display ...
16
votes
1answer
2k views

What is a Web Application Firewall?

What is a Web Application Firewall (WAF) and what are some of the things to look for in an effective one? Why would you deploy a WAF instead of just an IPS?
15
votes
4answers
4k views

Why users want to disable cookies?

I just started to create a new web application. In the documentation, it is written that I have to prepare for the situation where users have disabled cookies. This is not the first time I have read ...
15
votes
4answers
3k views

Is $_SERVER[ ] a safe source of data in PHP?

Can I 100% rely on $_SERVER[] to be a safe source of data that I do not need to sanitized like I do $_GET[] and $_POST[]? Thanks. OVERVIEW OF RESPONSES: So it seems there is a consensus that some ...
15
votes
4answers
1k views

My credit union is reducing its maximum password length to 10 characters

I just received an email from my credit union saying they are redesigning their online banking service and that I will need to change my password by October 22 to conform to the new limit of 10 ...
15
votes
5answers
5k views

Preventing information disclosure from browser back button/history?

I have sensitive data that will be hosted on a website, and I would like to prevent the data from being exposed in this scenario: The primary user logs off the application, but does not close the ...
15
votes
7answers
306 views

Is a “security measure” that doesn't provide a security benefit actually harmful?

If a security measure is implemented that doesn't provide any additional security benefit, can it be considered harmful? As an example, consider a login page where the user is asked to enter their ...
15
votes
4answers
1k views

Web Security Cheatsheet / ToDo list

Can anyone suggest a cheatsheet or ToDo list of web site and application security? A local small business owner prompted a question about web security, basically her company website just got XSS ...
15
votes
4answers
774 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 ...
15
votes
4answers
4k views

How to implement non-password authentication in a web site

In an answer to this question about pw reset, D.W. says: Lastly, consider non-password authentication. Passwords have many problems as an authentication mechanism, and you might consider other ...
15
votes
3answers
674 views

Getting a manual security code review done - What to watch out for?

We have a PHP application that we want to get code reviewed from an external security consultant, but I'm not clear on "how to" go about that process. We did specify what kind of tests he should be ...
15
votes
3answers
446 views

Are there any decent web app security scanners that can integrate with a build server?

I've spent a lot of time in TeamCity recently and the nightly code quality metrics coming from the dupe finder, FxCop and NDepend have been great. What I'd really like to do is find a decent web app ...
14
votes
6answers
4k views

Is showing your IP address in the URL a bad practice?

Someone told me that showing your IP address in a URL (like hxxp://45.67.134.34/default.html) is easier to hack. Is that true? I could trace any domain name and get its IP number as well.
14
votes
5answers
742 views

What is better, an established framework or a homebrew solution?

Recently, a website related to our university was hacked along with many others. This led to a general discussion1 on how to secure the website in the future. Anyway, there is one point that was ...
14
votes
6answers
1k views

Is This Login Security Enough?

I'm coming up with my next login system for admins of an ecommerce website to have login form is SSL secured password is converted to sha256 before being transmitted (bcrypt is too slow still for ...
14
votes
3answers
6k views

Is the Facebook login form using SSL without https in the URL?

If I go to http://facebook.com, I am not redirected to https://www.facebook.com. If it doesn't have https in the URL, can the login be secure? Usually I am redirected to an https page on other sites? ...
14
votes
3answers
3k views

Cross Site Scripting without special chars

I'm testing a web application and I found a XSS vulnerability. I can break a tag and inject some code to the application but nothing potentialy dangerous for the client. The application has a filter ...
14
votes
4answers
3k views

Is AJAX fundamentally insecure?

Possible Duplicate: How to do Ajax securely? At my workplace many people believe that AJAX is fundamentally insecure. I am under the impression that AJAX is exactly as secure as any other ...
14
votes
2answers
19k views

How to ensure that cookies are always sent via SSL when using ASP.NET on IIS 7.5?

Firesheep has brought the issue of insecure cookie exchanges to the forefront. How can you ensure that all cookie exchanges are forced to occur only via an SSL-secured connection to the server when ...
14
votes
4answers
594 views

Database Encryption Security

I am encrypting and decrypting my database data from my web applications API. If my web server is compromised, what is to keep someone from using that same method to retrieve the data? For example, ...
14
votes
3answers
2k views

Should security question answers be case-sensitive?

Question In the case of security questions being used to reset an account password, what is considered best practice for handling case-sensitivity on the security question answers? Scenario An ...
14
votes
2answers
609 views

Does it make sense to hash a session id before passing it to an advertisement partner?

My company runs a webshop. We work with a partner that gives discount vouchers to our customers after they buy (the vouchers can be used in other online shops) and also gives vouchers for our shop to ...
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 ...