Update description

Author: wvu

modules/exploits/unix/fileformat/imagemagick_delegate.rb

@@ -21,8 +21,9 @@ def initialize(info = {})
         a .png (for example) which is actually a crafted SVG (for example) that
         triggers the command injection.
 
-        Tested on Linux, BSD, and OS X. You'll want to choose your payload
-        carefully due to portability concerns. Use cmd/unix/generic if need be.
+        The PostScript (PS) target leverages a Ghostscript -dSAFER bypass
+        (discovered by taviso) to achieve RCE in the Ghostscript delegate.
+        Ghostscript versions 9.18 and later are affected.
 
         If ImageMagick supports popen(), a |-prefixed command will be used for
         the exploit. No delegates are involved in this exploitation.