Wednesday, September 10, 2008

Windows GDI+ GIF memory corruption

There is a memory corruption vulnerability in GIF file processing in Microsoft GDI+ that can be used to crash a vulnerable application and potentially execute arbitrary code.

The vulnerability

The vulnerability is caused due to improper handling of graphic control extension when processing malformed GIF files. The vulnerability can be triggered if a large number of extension markers (0x21) followed by unknown labels is found when processing a GIF file.


This vulnerability can be used to corrupt memory of any application utilizing GDI+ for GIF file decoding if it is used to open a malformed GIF file. This could lead to code execution with the privileges of the user running the vulnerable application.