Showing posts with label software security. Show all posts
Showing posts with label software security. Show all posts

Thursday, April 23, 2009

Blitz Blog: Quality Assurance Through Code Analysis

Today I read through a Parasoft whitepaper published on searchsoftwarequality.com, and I found it to be a great approach to static code analysis.

FULL DISCLOSURE: I write articles and am a “Software Testing Expert” for searchsoftwarequality.com. However, I do not blog positively if I don’t believe in the posting.

Parasoft is the manufacturer of an application security static code analysis tool. Of course, the white paper’s intention is to sell copies of their tool. Can’t fault them for 1) believing in their product and 2) wanting to pay the bills.

What I really like about this article is the approach they take to SCA. They are not pushing it as the end-all, be-all of code quality. They are very realistic about SCA, in fact, stating that it’s often over-used and, once over-used, ignored. Companies implementing SCA must be careful about it—don’t enable a rule unless you really want to enforce it.

At the same time, they make a strong point about the value of SCA. It can really help a team drive quality upstream. Some policies an engineering team might want to use, for example, contribute to code readability while other contribute to security (dynamically-built SQL statements vs. parameterized queries anyone?).

As an Agile engineer, I do take issue with their heavy-handed ‘management enforcement’ method. Agile teams need to adopt policies as needed. Cross-company Agile team representatives might establish company-wide policies and enforcement, but the Agile team itself should arrive at the bulk of the policy definitions.

One thing I like to see is the implementation of SCA directly in the build process – ie, no build if the code fails with errors, and a team-wide email on warnings. This is the best way to enforce policies (but teams need to be selective about policies, so they don’t overwhelm or ‘over-stay their welcome’).

Anyhow, blitz blog. Highly recommended reading!

http://go.techtarget.com/r/6673725/7930283/1

Friday, April 3, 2009

Found a Security Flaw (The Need for Software Testing Everywhere)

Today I was paying a bill online, and I crashed the company’s IIS server (I promise, I did nothing wrong—intentionally). The good news: they write their code rather securely, so they are using parameterized queries rather than embedded SQL statements. The bad news (besides the crash itself) is that they were running with tracing enabled, so I saw the entire stack trace.

I called the company and got in touch with their tech guy. He was really polite on the phone and very open to feedback. I shared a bunch of info with him and thought I ought to document it. So here’s an Open Letter to All Admins Running IIS:

· You need to check your machine.config (and possibly web.config) files and make sure <trace enabled=”false” localOnly=”true” pageOutput=”false” requestLimit=”10” traceMode=”SortByTime”/> See http://msdn.microsoft.com/en-us/library/aa302351.aspx for more info.

· Either spin up Microsoft Baseline Security Analyzer (MBSA) or use IISLockDown and URLScan to scan your server(s) security, especially in configuration. See http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=f32921af-9dbe-4dce-889e-ecf997eb18e9

· You might also benefit from a security review/audit from an experienced, independent consultant.

Security Focus has a decent article on the issue: http://www.securityfocus.com/infocus/1755 (it’s old but still accurate). NOTE there is a chance that running IISlockdown may break something. If your developers built the site with some dependency on what’s actually a security hole, locking down your server could cause issues. I highly recommend that you run this against a test deployment and then run all of your automated tests against that deployment, and that you do some manual testing.

You might also consider picking up copies of

  • “Improving Web Application Security” (MS Press),
  • “Building Secure Microsoft ASP.NET Applications (MS Press),
  • “Writing Secure Code” (I *highly* recommend this – it’s the bible on secure coding, especially in MS technologies), and
  • “Secure Development Lifecycle” (MS Press).

From more to less specific, these books are pointers on secure IIS configuration, ASP.NET coding, coding in general, and strategies for maintaining application security throughout lifecyles. The latter book is a great read if you’re on a larger team and/or need to influence management to give you the time for security-related work.

Friday, July 25, 2008

Software Quality Assurance: SDL (Secure Development Lifecycle

At work, I've been helping one of my teams implement portions of Microsoft's Secure Development Lifecycle (SDL). SDL is more than just plinking around attempting some penetration testing--it's a committed approach to secure software design. Here are some of the takeaways from our work:

  1. The first point I made with my team is that security features DO NOT EQUAL secure features. Having SSL encrypted communications does not make a web application secure! It just means you have an encrypted communications channel. Secure software isn't secure because of features such as Acegi security, RSA encryption or anything like it. Secure software is produced when developers think secure from the start. Secure software comes when code is written safely, when developers write solid, secure code, and when testers are helping with the planning and testing of the software with a secure focus.
  2. Next point we emphasized: threat modeling. As we wrapped up a two-hour threat modeling session, one of the developers commented "Why didn't we do this months ago, before our code was written!". Good point!! It's never too early to threat model. Analyze your product, paying special attention to where data crosses boundaries: user to Internet, Internet to server, server to database, etc. Model threats, wild and crazy or down-to-earth. Our threat modeling has resulted in 9 potential threats so far, and we expect several more as we continue.
  3. Security comes in layers. Back when I lived in India, I toured the Delhi fort. This fort was built by professionals. It has a deep moat around it. Tall, thick walls surround an inner wall, and inside that inner wall lies the fort. That's how our code should be! OK - so you're authenticated via Acegi and LDAP. You're encrypted with SSL. That's great - but what if someone logs in with a valid account, then tries to hijack another session? Your layered security will catch hacks like this--authorize anytime someone tries to access sensitive data. Even if you've already authenticated and authorized, do it again! Layers bring security.
  4. Reduce your footprint: in Agra, where the Taj Majal is, there's another fort (these Moguls were building forts everywhere!). This fort is on the edge of town, in the hills. Compared to the Taj, the fort is tiny. This is referred to as attack surface reduction. Only allow public access to a few of your resources. If you have features which suffer from weak security, disable them by default or remove them completely. Give hackers as little space as you can.
  5. Train your engineers (dev and test). There's common training needed by both (elements of secure design, running a threat model, etc.) and there are discipline-specific trainings such as penetration testing or the application of specific technologies. The SDL is called a lifecycle because it's a continuous process. Lather, rinse, repeat and all that.

Our training has produced benefits. For starters, developers have a new security-focused mind set. We've found a few security bugs already, and our threat model has exposed some potential issues. This is great progress, and it comes from just one day of work. Imagine what we'll be like in a few months after a day or two of training and a complete milestone with security in mind!

It's never too early or too late to take a step back and start thinking security. I designed our course based on my experience at Microsoft, which was neatly documented in Michael Howard's new book "SDL: Secure Development Lifecycle". I cannot recommend reading this book enough!

Got a security question? Post it here...