AppSec Blog: Category - Authentication

Four Attacks on OAuth - How to Secure Your OAuth Implementation

This article briefly introduces an emerging open-protocol technology, OAuth, and presents scenarios and examples of how insecure implementations of OAuth can be abused maliciously. We examine the characteristics of some of these attack vectors, and discuss ideas on countermeasures against possible attacks on users or applications that have implemented this protocol. An Introduction to the … Continue reading Four Attacks on OAuth - How to Secure Your OAuth Implementation

ASP.NET Padding Oracle Vulnerability

A very serious vulnerability in ASP.NET was revealed this past month that allows attackers to completely compromise ASP.NET Forms Authentication, among other things. When things like this happen, as developersit's important to see what lessons can be learned in order to improve the defensibility of our software. Source: 'Padding Oracle' Crypto Attack Affects Millions of … Continue reading ASP.NET Padding Oracle Vulnerability

Some Thoughts About Passwords

Passwords don't work. Any password has a finite chance of being guessed. A good password is just less likely to be guessed then a simple password. But a strong password is not necessarily the one with many weird characters but the one that is least likely guessed. Continue reading Some Thoughts About Passwords

Response to Nielsen's "Stop Password Masking"

I just ran across Jakob Nielsen's Alert Box post titled Stop Password Masking and wanted to provide some feedback from a security vs. usability perspective. I have great respect for Nielsen's contribution to the usability of the web. Back in the early days of the internet (mid 1990's), his books were gospel at my consulting … Continue reading Response to Nielsen's "Stop Password Masking"

Session Attacks and ASP.NET - Part 2

In Session Attacks and ASP.NET - Part 1, I introduced one type of attack against the session called Session Fixation as well as ASP.NET's session architecture and authentication architecture. In this post, I'll delve into a couple specific attack scenarios, cover risk reduction, and countermeasures. Attack Scenario: ASP.NET Session with Forms Authentication So understanding the … Continue reading Session Attacks and ASP.NET - Part 2