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Firefox Patches DLL Load Hijacking Vulnerability

Security release fixes 15 bugs and adds defense against clickjacking attacks.



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On Tuesday, Mozilla released two new versions of Firefox -- 3.6.9 and 3.5.12 -- to patch 15 vulnerabilities, 10 of which it rated as being "critical." Most notably, Firefox is now immune to the DLL load hijacking vulnerability affecting numerous Windows applications.

Security-wise, the new Firefox 3.6 also adds support for the X-Frame-Options HTTP response header. According to Mozilla, "site owners can use this to mitigate clickjacking attacks by ensuring that their content is not embedded into other sites." In particular, the feature will deny all iframes outright, or else only allow frames that have the same origin as the main page. This functionality should help website operators such as eBay reduce the incidence of clickjacking attacks on their sites.

On Tuesday, Apple issued its own patch for Safari against the DLL load hijacking vulnerability, amongst other fixes, with the release of Safari 5.0.2 and Safari 4.1.2. Apple said that due to the vulnerability, in previous versions of Safari for Windows, "attempting to reveal the location of a downloaded file may execute an application contained in that directory, which may lead to arbitrary code execution."

With Firefox, Safari, and Opera now patched against the DLL load hijacking -- aka "binary planting" and "DLL preloading attacks" -- plus Internet Explorer and Google Chrome already apparently immune to such attacks, browsers now appear to be safe. Unfortunately, however, many other applications have yet to be patched.

Indeed, according to a list being maintained by vulnerability research firm Secunia, to date there are at least 118 products, across 45 vendors, affected by the DLL issue. But only 12 of these products have been patched against the DLL load hijacking vulnerability.

Last week, Microsoft released a hotfix to help mitigate the vulnerability, and provided more details about how related exploits work. In particular, Microsoft's Security Research & Defense blog recently published a detailed walk-through of how such attacks unfold, from a user's perspective, and offered guidance on how to best employ its attack mitigation tool.

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Kirsten Powell, Senior Manager for Security & Risk Management at Adobe
Joshua Goldfarb, Director of Product Management at F5