This indicates an attack attempt to exploit a Remote Code Execution vulnerability in Microsoft Windows.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted PDF file. An attacker can exploit this by tricking an unsuspecting user into open a crafted PDF file and execute arbitrary code within the context of the application.
Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.