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

learn more… | top users | synonyms

13
votes
4answers
587 views

How to protect off-the-shelf web applications?

As an exercise, please consider the following: If you are faced with having to deploy off-the-shelf web applications that you are unsure about the vendors security coding practices, which techniques ...
13
votes
4answers
465 views

What are the most important security checks for new web applications?

I'm wondering what are the top priority security checks you should make befor launching a new webapp? I'm guessing brute force vulnerabilities and cross-site scripting. What are the other things you ...
13
votes
2answers
1k views

How to not reveal that you are using PHP?

I'm bulding a website but some webtools and browser plugins allows anyone to get information on which technologies the website has been built. Is there any Alternative to not reveal that we are ...
13
votes
3answers
541 views

Does signing out of a website ensure no-one can cookie hack?

If I click the signout link of a website, does this mean it is not possible for someone to hijack my cookie and sign in with it? While I'm logged in, is it possible for someone who has access to my ...
13
votes
2answers
2k views

Best practice in web application security authentication to avoid bruteforce attack

I want to cover the possible cases of attacking. My application already has captcha and two-factor authentication, but how can I avoid a tiny attack without annoying my users? The possible cases that ...
13
votes
3answers
322 views

Malicious QR Code and Mitigation

I just started reading a little on QR code, so I'm not entirely familiar with QR Code capabilities, but a thought crossed my mind today. I scanned a QR Code on a postcard I received, and it ...
13
votes
6answers
7k views

Disable insecure/dangerous PHP functions

Typically my job description limits me to code-review of web applications. More recently I've been asked to assist with some server-side PHP optimization where, although I am familiar with it, I lack ...
13
votes
3answers
856 views

Elaborate websockets security

I'm interested in learning more about web sockets security. Read that web sockets were originally in Firefox, removed for security reasons and now added back in with the problem resolved: ...
13
votes
2answers
180 views

Would suggesting a random passphrase during sign-up hurt overall security?

I've been looking for ways to improve security and security awareness for both internal and external clients and I happened upon the idea of generating a one-time, random "password suggestion" on the ...
13
votes
2answers
790 views

How can I test my web application for timing attacks?

race conditions, etc. Are there automatic tools for this? What manual techniques should I use? From the Area51 proposal
13
votes
2answers
459 views

Detecting website attack attempts

I am currently trying to implement some recommendations from OWASP AppSensor Project and I'd like to respond to attacker, when he tries to break into my website. Is there any resource ...
12
votes
7answers
1k views

Where to start with security testing?

Starting with a QA team that deals mainly with functional requirements testing and has little real security testing experience, what simple practical things should the QA team start doing to start ...
12
votes
4answers
325 views

Sensitive information was placed in a publicly accessible folder. Who is responsible and how to proceed?

Background We have an IT staff who manages our server and a web developer who is not on the IT staff and has no root access to the server. All involved do very high quality work and I do not consider ...
12
votes
4answers
524 views

How should I secure a contact form that appears on every page of a website?

My client has a small "Contact Us" form on every page of their website. They are adamant about not including CAPTCHA verification on these forms, to keep them easy to use, but I feel it is my ...
12
votes
4answers
580 views

What does defense in depth entail for a web app?

I'm assuming it means different layers of security from app-level security to server hardening to personnel training, but what are each of those layers and what are some good resources for each level ...
12
votes
6answers
3k 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 ...
12
votes
3answers
3k views

Security risks with JSONP?

What are the security risks with JSONP? Is using JSONP in a new web application reasonable, from a security perspective, or is it better to use a different method for cross-origin web mashups? If ...
12
votes
1answer
3k views

enable browser caching with HTTPS

I understand that sensitive data should not be cached (ie, you dont want to cache an HTML file with all of your bank account details in it), but there are some things that HTTPS protected sites should ...
12
votes
3answers
1k views

Asp.net mvc security check list

I am planning to start a new web site on asp.net mvc 2 (3). Have anybody a full (if possible) check list of actions, approaches I should reach to avoid almost problems with security.
12
votes
4answers
5k views

Session Hijacking - regenerate session ID

Does regenerating the session ID on each request mitigate the probability of a session hijack enough to be worth implementing? I would imagine combining a check for REMOTE_ADDR vs the REMOTE_ADDR ...
12
votes
3answers
624 views

What does a HTML filter need to do, to protect against SVG attacks?

I recently learned that SVG (Scalable Vector Graphics) images introduce a number of opportunities for subtle attacks on the web. (See paper below.) While SVG images may look like an image, the file ...
12
votes
6answers
1k 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
4answers
1k views

Preventing reverse-engineering of client application

I have a web service which is used by a Flash client. Both the service and the Flash client is produced by me (read: my company). The Flash client communicates with the server over HTTPS. One of the ...
11
votes
5answers
27k views

Testing for HTTP TRACE method

How can I test for HTTP TRACE on my web-server? I need to train a Tester how to verify that the HTTP TRACE method is disabled. Ideally I need a script to paste into Firebug to initiate a https ...
11
votes
2answers
2k views

What does this injected code do?

One of my sites has just been hacked as this code has been inserted into random(?) files and places within the files. Does anyone understand what it is trying to do? I would welcome anything that may ...
11
votes
5answers
3k views

What is a DoS Attack and how does it differ from a DDoS attack?

Can some one explain to me the concept of Dos Attacks for web applications ? Also what is the distinction between Dos and Distributed Dos ( ie DDos) attacks ? Wikipedia says : In computing, a ...
11
votes
7answers
2k views

Should we force user to HTTPS on website?

Should we force website from HTTP to HTTPS , one of the method is using .htaccess: RewriteCond %{SERVER_PORT} 80 RewriteRule ^(.*)$ https://www.example.com/$1 [R,L] But what I notice is that some ...
11
votes
6answers
6k views

Why are iframes allowed at all in modern browsers?

I read a number of IT security blogs (though I'm no security expert), and it seems a significant percentage of exploits in the wild are delivered through adding malicious iframes to a hacked website, ...
11
votes
4answers
9k views

How to know which database is behind a web application?

I've read that different databases (mysql, sql server,...) have different vulnerabilities and that they are vulnerable to some specific sql injections. When attacker try to perform a database attack ...
11
votes
6answers
2k views

Is there a security risk running web apps in debug=“true”?

This is a copy of the original question on Stack Overflow which didn't get much love and is probably more relevant here: There are plenty of performance reasons why apps shouldn't be run in ...
11
votes
3answers
573 views

Is stripping out < and > characters an effective way of preventing XSS?

I'm guessing that HTML encoding the input would probably be a better solution, but I'm curious if just stripping out any < and > characters would be an effective defense against XSS attacks. ...
11
votes
4answers
3k views

Challenging challenge: client-side password hashing and server-side password verification

We have a website where users need to log in to access privileged information. Obviously we are using SSL, but I also want to avoid plaintext passwords from accidently ending up in server logs, or ...
11
votes
2answers
9k 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 ...
11
votes
4answers
942 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 ...
11
votes
3answers
796 views

How much information about the reason for an unsuccessful login should a web application give?

After an unsuccessful login attempt, should I inform the user about its reason? Or more generally, how much information about the reason for an unsuccessful login attempt should a web application ...
11
votes
2answers
976 views

Interpolique: transparently preventing SQL Injection and XSS with base64 encoding, what happened?

For the keynote at The Next HOPE a couple of years ago, Dan Kaminsky unveiled Interpolique (the talk is really fun btw). The problem he raised was how to defend against injection attacks, including ...
11
votes
1answer
2k views

Best way to secure javascript front end/REST back end architecture web site?

I would like to build the following project: public REST API back end which can be accessed by any authenticated client. front end with static files in HTML/CSS/Javascript with Backbone.js jQuery ...
11
votes
1answer
685 views

Webapp2 security

I am coding a REST web application that runs on Google App Engine, it authenticates API requests to privileged data using sessions by cookies provided by webapp2_extras.auth and ...
10
votes
4answers
3k views

Authenticating without a database

I've been inspired by a question over on Code Review, which boils down to: What is the proper way to authenticate a user without a database? Would it be the exact same process if you stored ...
10
votes
7answers
1k views

Whitelisting DOM elements to defeat XSS

As we know, developers are responsible for correctly escaping/validating data provided by the user before rendering or storing them. However, we must agree that it's relatively easy to forget a single ...
10
votes
8answers
2k views

What chars should I not allow in passwords?

I am planning to develop a website that require that the users register a username and a password. When I let the user choose a password, what chars should I allow the users to have in the password? ...
10
votes
6answers
1k views

Is XSS a server-side or client-side vulnerability?

My colleagues claim that XSS is a vulnerability on the server side. I always thought that this is a client side vulnerability. Which one of us is correct, and why?
10
votes
6answers
3k views

Security review: “HTTP header user-agent has been set to (something)”

We got a security review done of our PHP code and they team advised this in their report (amongst other things): /appdir/ Details The HTTP header user-agent has been set to \" . Request GET ...
10
votes
4answers
356 views

Should a web application return true http errors?

Exception and error information can be used by a malicious user to map out the API of an web application, so it is routine to see security checklists to advise returning only a "Please contact your ...
10
votes
5answers
9k views

Benefits of identifying clients based upon the “X-Forwarded-For” or similar HTTP header in addition to Client IP

The X-Forwarded-For header is used by some HTTP proxies to identify the IP address of the client. The wiki page (linked above) mentions that ISPs may use this header as well. In addition there are a ...
10
votes
7answers
684 views

IP address black list

My website has a black list of IP addresses. The web application, in some way, detects all invalid, suspicious influences to it and remembers IP address and denies any requests from that IP address. ...
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 ...
10
votes
2answers
979 views

What are the SQL-injections issues of parameterized queries?

I've written some code to generate an SQL query in ASP classic. I'm not sure if it's secure or not: Set adoCon = Server.CreateObject("ADODB.Connection") adoCon.Open "Provider=Microsoft.Jet.OLEDB.4.0; ...
10
votes
4answers
4k views

Generate cryptographically strong pseudorandom numbers in Javascript?

Is there any good way to generate cryptographically strong pseudorandom (or true random) numbers in Javascript? The crucial requirement: if a.com's Javascript generates some random numbers, no one ...
10
votes
3answers
389 views

Should I ask a user to re-authenticate if the browser thumbprint changes? Is a server side library available?

Is there a security benefit to using the browser's thumbprint in addition to a session identifier to identify a unique session? Would it then be advisable to ask the user to reauthenticate (or simply ...