Fortinet Discovers Google Chrome Skia Engine Heap Overflow Vulnerability
Fortinet's FortiGuard Labs has discovered a heap overflow vulnerability in Google Chrome Skia engine.
Skia is an open source 2D graphics library which provides common APIs that work across a variety of hardware and software platforms. It serves as the graphics engine for Google Chrome and Chrome OS, Android, Mozilla Firefox and Firefox OS, and many other products. The Skia image rendering engine contains several Effect Filters which can be applied to an pre-existing sourced Bitmap Image or to a new Skia Drawing.
The heap overflow vulnerability is caused due to an incorrect bounds check in SkRegionPriv whilst implementing the Skia Filter SkAlphaThresholdFilter. The malformed data supplied to the SkAlphaThresholdFilter filter escapes the bounds set in SkRegionPriv which leads to a heap-based buffer overflow. Thus this vulnerability can be triggered by loading a malicious webpage wherein malformed input data is provided to the Skia SkAlphaThresholdFilter Effect Filter, thereby causing the Skia rendering engine to crash.
SolutionsFortiGuard Labs released the following FortiGate IPS signature which covers this specific vulnerability:
Released Mar 14, 2017
Users should apply the solution provided by Google.
Chrome version 57.0.2987.87 and before are affected.