added leviathan

clusters/threat-actor.json

@@ -2477,6 +2477,20 @@
         ],
         "country": "KP"
       }
+    },
+    {
+      "value": "Leviathan",
+      "description": "Leviathan is an espionage actor targeting organizations and high-value targets in defense and government. Active since at least 2014, this actor has long-standing interest in maritime industries, naval defense contractors, and associated research institutions in the United States and Western Europe.",
+      "meta": {
+        "refs": [
+          "https://www.proofpoint.com/us/threat-insight/post/leviathan-espionage-actor-spearphishes-maritime-and-defense-targets",
+          "https://www.fireeye.com/blog/threat-research/2018/03/suspected-chinese-espionage-group-targeting-maritime-and-engineering-industries.html"
+        ],
+        "synonyms": [
+          "TEMP.Periscope"
+        ],
+        "country": "CN"
+      }
     }
   ],
   "name": "Threat actor",