[threat-actors] Add Ruby Sleet

clusters/threat-actor.json

@@ -14379,6 +14379,20 @@
       },
       "uuid": "b80be7a7-6d06-4da7-8ae0-302a198e7c73",
       "value": "Lilac Typhoon"
+    },
+    {
+      "description": "Ruby Sleet is a threat actor linked to North Korea's Ministry of State Security. Cerium has been involved in spear-phishing campaigns, compromising devices, and conducting cyberattacks alongside other North Korean threat actors. They have also targeted companies involved in COVID-19 research and vaccine development.",
+      "meta": {
+        "country": "KP",
+        "refs": [
+          "https://blogs.microsoft.com/on-the-issues/2020/11/13/health-care-cyberattacks-covid-19-paris-peace-forum/"
+        ],
+        "synonyms": [
+          "CERIUM"
+        ]
+      },
+      "uuid": "03ff54cf-f7d4-4606-a531-2ca6d4fa6a54",
+      "value": "Ruby Sleet"
     }
   ],
   "version": 298