Critical vulnerabilities in Windows and Adobe Reader exposed by hacker

A hacker has published an extensive list of Adobe Reader and Windows vulnerabilities based on his research into a relatively obscure area of font management.

Google Project Zero hacker Mateusz Jurczyk found a total of 15 vulnerabilities, any of which could trigger remote code execution or privilege escalation in Adobe Reader or the Windows kernel. However, the two worst (detailed as CVE-2015-3052 for 32-bit and CVE-2015-0093 for 64-bit) exist in the Adobe Type Manager Font Driver, which has existed in the Windows kernel since Windows NT 4.

He told IT blog the The Register that the most serious, an ‘entirely reliable’ BLEND instruction exploit relates to the handling of CharStrings that are responsible for drawing the shape of each glyph at a particular point size.

“The extremely powerful primitive provided by the vulnerability – together with the fact that it affected all supported versions of both Adobe Reader and Microsoft Windows thus making it possible to create an exploit chain leading to a full system compromise with just a single bug – makes it one of the most interesting security issues I have discovered so far,” Jurczyk said.

“The video demonstrates reliable exploitation of a vulnerability in the handling of the BLEND instruction in Type 1 fonts, used in two stages to first achieve arbitrary code execution in Adobe Reader 11.0.10, and further escape the sandbox and elevate privileges to System by attacking the Adobe Type Manager Font Driver in the Windows 8.1 Update 1 32-bit (or 64-bit) kernel”, he continued.

In a blog post the researcher also shared his presentation from the Recon security conference this month called ‘One font vulnerability to rule them all: A story of cross-software ownage, shared codebases and advanced exploitation.’

As welivesecurity.com recently reported, Google has extended the disclosure period for vulnerabilities uncovered in its Project Zero program by an additional two weeks, if a vendor is planning a patch in the two weeks following the deadline. The additional 14 day ‘grace period’ for vendors will “improve industry response times to security bugs, but will result in softer landings for bugs marginally over deadline”, according to Google.

by Karl Thomas, ESET


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