Archive for the Clickjacking Category

NSA++, NoScript on Android

NSA++ (NoScript Anywhere Plus Plus, or NoScript 3.5 alpha for Android Native) has been in the works for a while now, and it’s finally ready for prime time, thanks also to the continuous help of the NLNet Foundation.

Even if it’s not as complete as its legacy Electrolysis-orphaned obsolete predecessor (NSA, designed for the now discontinued XUL Fennec, AKA Firefox 4 Mobile) yet, NSA++ already provides the best security you can get in any mobile browser: beside its trademark flexible script blocking facility, it features the first ever and still strongest XSS filter available, plus partial but functional portings of the unique ClearClick anti-Clickjacking technology and ABE’s firewall/LAN CSRF protection.

You can read more or try it with a recent Firefox Nightly (mobile or desktop, too!) on the NSA project page.

Last week a couple of interesting and novel Clickjacking techniques have been published:

  1. Cross-domain content extraction via framed view-source
  2. Double-clickjacking (or, as I prefer to call it, Rapid fire cross-site interaction)

Both involve a tiny amount of social engineering (#2 requires JavaScript, too), but as you can see they are totally feasible.

Needless to say, recent NoScript versions neutralize them no matter if JavaScript is enabled or not, thanks to specific enhancements in NoScript’s unique anti-Clickjacking protection module, ClearClick.

ClearClick anti-Clickjacking on Android

NoScript 3.0a3 for Firefox Mobile is out, bringing three of the major “classic” NoScript features to your Android smartphones:

  1. Easy per-site active content permissions management.
  2. The first and most powerful anti-XSS (cross-site scripting) filter available in a web browser.
  3. ClearClick, the one and only effective client-side protection against Clickjackings available on the client side.

Still some road ahead for convergence between the desktop and the mobile versions, but we’re already past the biggest challenges…

A huge thanks to the NLNet foundation, and to many individuals, institutions and companies using NoScript, for their generous support to this project.

As you probably know, ClearClick is the only effective client-side protection against Clickjacking (AKA UI Redressing).

A couple of weeks ago, Atul Agarwal of Secfence privately reported me a ClearClick bypass based on tracking user’s mouse movements and dynamically putting an extremely small click target just under his pointer. Even though it required the attacker’s page to be whitelisted and run JavaScript, I deemed this bug deserved to be fixed ASAP because ClearClick, like most web application security countermeasures offered by NoScript (e.g. anti-XSS, ABE or HTTPS enforcement) is guaranteed to work independently from script permissions, i.e. even if you allow scripts globally. Atul kindly accepted to coordinate the disclosure, so I immediately released the 2.0.9.7rc1 development build with the bug fix, and all the user base was automatically updated with the stable 2.0.9.7 release about one week later.

BTW, looks like Sophos likes ClearClick and dirty female teachers very much :)

Michael Coates just announced that X-Frame-Option will be finally available on Firefox starting with the next minor update, 3.6.9.

This is great news, because it puts vanilla Firefox on par with IE and Chrome regarding this server-side defense, which security-aware web authors (like the guys at Google, and possibly the AMO team now) can use, by modifying the way their pages are served, in order to protect their web sites against frame-based Clickjacking.

I said “vanilla”, because Firefox with NoScript has been supporting X-Frame-Options since the day after it had been announced with much fanfare by Microsoft, i.e. Jan the 29th 2009 (more than 1 year and half, now). Mostly as a point of pride, actually, than out of a true necessity, since the existent NoScript’s ClearClick module already provided a more complete and effective protection against all kinds of Clickjacking (either frame-based or plugin-based), independently from the good will and security awareness of server-side implementers.

It’s worth to mention that in many situations, like on web properties which provide some kinds of frame-based APIs, or support external apps and “widgets”, X-Frame-Options is hard or impossible to be configured properly, because it would break the business model of the site itself. Facebook is a glaring example of this kind of sites, vulnerable to Clickjacking, where X-Frame-Options would fall short. Needless to say, NoScript’s ClearClick does protect against Clickjacking everywhere, no matter if web site owners could not, or choose not, to implement X-Frame-Options (or just didn’t know about it!).

To be fair, there’s an upcoming Firefox 4 technology which can better help web developers protecting their web sites against this and other web application security issues, even in complex scenarios like Facebook’s: it is Content Security Policy (CSP). I’d really love it to get popular enough among security-aware developers, and possibly be standardized across browser implementations.

On the other hand, as long as you don’t trust every web site out there to always do the right thing security-wise, NoScript will be your friend :)

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