This indicates an attack attempt against a remote Code Execution vulnerability in Foxit Reader and PhantomPDF.
The vulnerability is due to an error when the vulnerable software processes specially crafted PDF files with malformed JPXDecode streams.A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted PDF file.
Foxit Reader 126.96.36.1994 and earlier on Windows
Foxit Reader 2.0.0.0625 and earlier on Mac OS X
Foxit Reader 1.1.1.0602 and earlier on Linux
Foxit PhantomPDF 188.8.131.528 and earlier on Windows
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.