This indicates an attack against an Information Disclosure vulnerability in ImageMagick.
The vulnerability is caused by improper validation of image files. A remote attacker may be able to exploit this to gain access to sensitive information on the affected system, via a crafted file.
ImageMagick Studio ImageMagick before 7.0.8-9
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the most recent upgrade or patch from the vendor.