Friday, May 8, 2009

Incredulous Interactions with Web Application Developers: 2 of Many



Here's wishing that all of you have a good weekend. I left early from the office today to attend to some household duties. While I was sitting and watching TV, I came up with a concept, which resulted in this title. I interact with several application developers over the past few years and now as I steeped in AppSec, I have been interacting with a lot of Web Application Developers during my application assessments. Normally, they are a nice bunch, who are quite convinced about the authenticity of my claims of having their applications torn apart on the internet. But, everytime I discuss security, there are always this few developers who end up astounding me or completely disarming my constant efforts to bring about change in the way they think (or don't think) about Web Application Security . I thought, "Why not chronicle my interactions with these people, for the benefit of the community, and for a few laughs (or atleast a smile) in the normally tense lives of security folk?", and so, I present to you, the second in the series of "Incredulous interactions with Web Application Developers". You might be wondering what happened to the first of the series. It is the first entry in this blog, but has not been grouped under this title. Anyway here it goes....

It was at the end of the day, and I had almost finished assessing this application. The application was being developed by a small group of developers working for a small company. Their product claimed to be the only one of its kind and one of their potential clients wanted the application to reviewed for security.

I had reviewed the Application for over 2 days. I had spent some time interacting with the project manager and the developers, and had performed a combination of black and white-box tests on the application. The application had some serious issues, there was almost no validation and whatever little validation it had, it was on the client-side, utilizing trusty old Javascript. I knew it was a problem. The developers were quite sold when I showed them a Cross Site scripting PoC as well as a Embedded Flash injection PoC. The only problem was getting through to the Project Manager. He was not convinced, and a conversation on the following lines ensued.

I used Burp proxy to perform my scripting attacks and he said this. "This application is going to be used only by the Company employees. why will they want to steal this data from the company?", for which I gave him standard insider threat lecture, statistics, et all. I tried explaining to him the fact, that this application stored extremely sensitive data (which it did) and an insider would also have a clear motivation to break into the application to steal information, not to mention disgruntled employees, or other employees with malicious intent. I also explained to him the CSRF angle, where this site might be attacked by another site violating the same origin policy.

He was yet unconvinced and he said, trying desperately to prove a point, "I have worked for over 12 years in Software development and have developed dozens of applications, never before has a client asked me for all the security features you are asking me for, it seems that you just want to prove a point." I burst out laughing at this and told him that if he believed that his potential clients weren't concerned about security, then they wouldn't have engaged my services to perform the assessment. I also had to tell him, that the way he or anyone else has been developing web apps in the cavalier manner that they have been all these years, does not make it right. Quantity is not quality, I told him and I also informed him of the fact, that awareness has been rising in the community about the effects of web application attacks, which is the reason why, if he wants his product to remain competitive and viable in any market, he would have to do "complicated things" like input validation based on a whitelist of "known good" characters to prevent against a smorgasbord of attacks. I told him finally that it would be for the benefit of the application and the data it holds as all these measures would prevent against any untoward incidents and not result in loss of reputation for his company. The man finally backed down after that and we discussed some implementation strategies for input validation across his web app.

This got me thinking, that developers have churned out several thousands of web applications which are working all over the internet and organizational intranets over the years. This was a single project manager from a single small company, who had himself been involved in the development of over 20 applications in his career. It would be quite scary to think of other developers over the years who would have developed similar applications with similar if not worse vulnerabilities.........

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The views presented in this blog are entirely mine and are not those of my company.

© Abhay Bhargav 2010