HACK THE BOX | PETPET | PLI/Pillow | RCE | CVE-2018-16509
Ghostscript, a software suite for interpreting Adobe Systems' PostScript and PDF languages, can be found on production servers, even if no direct applications use it. It's often installed as a dependency, for instance, with ImageMagick. Several vulnerabilities have been discovered in Ghostscript, including CVE-2018-16509, which allows for the execution of arbitrary commands. This vulnerability can be exploited when a failed restore (grestore) in PostScript occurs, disabling LockSafetyParams and avoiding invalidaccess. It's reachable via libraries like ImageMagick or programming language libraries that use Ghostscript, such as PIL/Pillow.