This indicates an attempt to exploit a Remote Code Execution vulnerability in Microsoft Windows.
The vulnerability is caused by an error when the vulnerable system handles a malformed ".PPSX" file. A remote attacker may be able exploit this by enticing a user to open a crafted ".PPSX" file and execute arbitrary code on the target system.
Microsoft Windows Vista SP2
Windows Server 2008 SP2 and R2 SP1
Windows 7 SP1
Windows Server 2012 Gold and R2
Windows RT Gold and 8.1
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the patch, available from the web site.