AppSec Blog: Author - SANS Institute

AppSec Blog:

Clickjacking: Help, I Was Framed!

Security researchers discovered and disclosed the Clickjacking attack (also known as a "UI Redress Attack") back in 2008. All major browsers were affected. Flash even had an interesting vulnerability that allowed control of a user's microphone and webcam. Yet, here we are 7 years later still citing this issue on nearly every security assessment of web applications that we do. During our report delivery, development teams typically have one of the following responses: "What's Clickjacking?", "What can someone really do with this?", or "So what?".

I'd like to take a minute to explain a little bit about this exploit, give a quick example, and talk about a few ways to mitigate this issue.

The Exploit

Clickjacking involves hosting a form from the application in an iframe and tricking the user into activating the form. A common way to do this is to set the opacity of the iframe to 0 (rendering it invisible) and placing a link over a button on the

...

Demystifying Cross-Site Request Forgery

Continuously ranked in the OWASP Top Ten, a large majority of the development community still doesn't understand Cross-Site Request Forgery (CSRF). After years of penetration tests and code reviews, my experiences show that a high percentage of applications, especially new applications, do not have proper CSRF protections in place. This post provides a refresher on CSRF and provides a common defense for this issue.

The Exploit

CSRF occurs when an application trusts that all requests originating from the user's browser are user-directed actions. Imagine that you are logged into your bank's online portal. The application requires users to authenticate and passes a session cookie back to the browser. Subsequent requests made to the banking site must contain the session cookie, allowing the site to identify the user and perform the requested action.

What if an attacker could send a fake request using the victim's browser?

Suppose an attacker wants to

...

Password Storage Mistakes

Steve Kosten is an instructor with the SANS Institute for DEV541: Secure Coding in Java/JEE.

Password Storage Mistakes

I was visiting a web site recently that I haven't visited in many, many years. I tried a few old passwords I used to use before I started using a password storage system, but no luck. I was defeated. Barred from entry into this site. But wait, they have a "Forgot Password" link; knowing I will soon have entry into the site, I confidently click on that link (after entering what I believe my username is). Boom, a few seconds later, I have an email from this web site that I will not name. Opening the email, there it was. The password I had created from ages ago. Head-slap.

The head slap wasn't for me forgetting my password; what were the developers of this site doing storing MY PASSWORD in clear text??!! Where anyone with

...

REST Security Protections

Greg Leonard is an instructor with the SANS Institute for DEV541: Secure Coding in Java/JEE.

REST Security Protections

Representational State Transfer (REST) has become popular in modern web application development. They take advantage of HTTP, a well established web communication protocol, and provide a simple-to-understand framework for delivering a flexible and highly performant content delivery method for web services (known as RESTful services). However, adoption of REST has seen some resistance as it does not include any standards for security. This means that every service developed that wants to provide authentication, authorization, validation, encoding, or any other security concern is essentially on their own. Clients that want to consume these services are likewise responsible for creating custom interfaces for every REST service

...

LinkedIn OAuth Open Redirect Disclosure

During a recent mobile security engagement, I discovered an Insecure Redirect vulnerability in the LinkedIn OAuth 1.0 implementation that could allow an attacker to conduct phishing attacks against LinkedIn members. This vulnerability could be used to compromise LinkedIn user accounts, and gather sensitive information from those accounts (e.g. personal information and credit card numbers). The following describes this security vulnerability in detail and how I discovered it.

The Vulnerability
Section 4.7 of the OAuth 1.0 specification (RFC 5849) warns of possible phishing attacks, depending on the implementation. A vulnerable OAuth implementation could enable phishing attacks via user-agent redirection. The stated emphasis, further supported by OAuth 2.0 (RFC 6749 via "redirect_uri" parameter), is intended to raise awareness of open-redirection as a security vulnerability that should be avoided.

...