Threat fields usage and examples

Serverless Stack

The threat.* fields map threat indicators to ECS. The data helps detect malicious events with indicator match rules and enrichment.

Indicators

Threat intelligence indicators come from many sources in different structures. Normalize these indicators using the ECS threat.indicator.* fields. Once normalized, consistently query indicators from various sources and build indicator match rules.

The below example is from an online database. It contains several network indicators from a known malware site.

{
    "@timestamp": "2019-08-10T11:09:23.000Z",
    "event": {
        "kind": "enrichment",
        "category": "threat",
        "type": "indicator",
        "severity": 7,
        "risk_score": 10.0,
    },
    "threat: {
        "indicator": {
            "first_seen": "2020-11-05T17:25:47.000Z",
            "last_seen": "2020-11-05T17:25:47.000Z",
            "modified_at": "2020-11-05T17:25:47.000Z",
            "sightings": 10,
            "type": [
                "ipv4-addr",
                "port",
                "domain-name",
                "email-addr"
            ],
            "description": "Email address, domain, port, and IP address observed during an Angler EK campaign.",
            "provider": "Abuse.ch",
            "reference": "https://urlhaus.abuse.ch/url/abcdefg/",
            "confidence": "High",
            "ip": 1.2.3.4,
            "port": 443,
            "email.address": "[email protected]",
            "marking": {
                "tlp": "CLEAR"
            },
            "url": {
                "domain": "malicious.evil",
            },
            "scanner_stats": 4
        }
    },
    "related": {
        "hosts": [
            "malicious.evil"
        ],
        "ip": [
            1.2.3.4
        ]
    }
}

Use the enrichment value for event.kind.
Use the threat value for event.category.
The event type is set to indicator.
Capture indicator details at threat.indicator.*.
Copy indicators to the relevant related.* fields.

The following example maps a file-based indicator.

		{
    "@timestamp": "2019-08-10T11:09:23.000Z",
    "event": {
        "kind": "enrichment",
        "category": "threat",
        "type": "indicator",
        "severity": 7,
        "risk_score": 10,
        },
    "threat": {
        "indicator": {
            "first_seen": "2020-11-05T17:25:47.000Z",
            "last_seen": "2020-11-05T17:25:47.000Z",
            "modified_at": "2020-11-05T17:25:47.000Z",
            "sightings": 10,
            "type": [
                "file"
            ],
            "description": "Implant used during an Angler EK campaign.",
            "provider": "Abuse.ch",
            "reference": "https://bazaar.abuse.ch/sample/f3ec9a2f2766c6bcf8c2894a9927c227649249ac146aabfe8d26b259be7d7055",
            "confidence": "High",
            "file": {
                "hash": {
                    "sha256": "0c415dd718e3b3728707d579cf8214f54c2942e964975a5f925e0b82fea644b4",
                     "md5": "1eee2bf3f56d8abed72da2bc523e7431"
                },
                "size": 656896,
                "name": "invoice.doc"
                },
            "marking": {
                "tlp": "CLEAR"
            },
            "scanner_stats": 4
        }
    },
    "related": {
        "hash": [
            "1eee2bf3f56d8abed72da2bc523e7431",
            "0c415dd718e3b3728707d579cf8214f54c2942e964975a5f925e0b82fea644b4"
        ]
    }
}
		
	

Use the file value for threat.indicator.type.
Capture file attributes at threat.indicator.file.*.
Again, populate the related.hash field with the file hashes.

Enrichments

Event enrichment searches for known threats using an event’s values and, if found, adds those associated details.

		{
  "process": {
    "name": "svchost.exe",
    "pid": 1644,
    "entity_id": "MDgyOWFiYTYtMzRkYi1kZTM2LTFkNDItMzBlYWM3NDVlOTgwLTE2NDQtMTMyNDk3MTA2OTcuNDc1OTExNTAw",
    "executable": "C:\\Windows\\System32\\svchost.exe"
  },
  "message": "Endpoint file event",
  "@timestamp": "2020-11-17T19:07:46.0956672Z",
  "file": {
    "path": "C:\\Windows\\Prefetch\\SVCHOST.EXE-AE7DB802.pf",
    "extension": "pf",
    "name": "SVCHOST.EXE-AE7DB802.pf",
    "hash": {
      "sha256": "0c415dd718e3b3728707d579cf8214f54c2942e964975a5f925e0b82fea644b4"
    }
  },
  "threat": {
    "enrichments": [
      {
        "indicator": {
          "marking": {
            "tlp": "CLEAR"
          },
          "first_seen": "2020-11-17T19:07:46.0956672Z",
          "file": {
            "hash": {
              "sha256": "0c415dd718e3b3728707d579cf8214f54c2942e964975a5f925e0b82fea644b4",
              "md5": "1eee2bf3f56d8abed72da2bc523e7431"
            },
            "size": 656896,
            "name": "invoice.doc"
          },
          "last_seen": "2020-11-17T19:07:46.0956672Z",
          "reference": "https://system.example.com/event/#0001234",
          "sightings": 4,
          "type": [
              "sha256",
              "md5",
              "file_name",
              "file_size"
        ],
          "description": "file last associated with delivering Angler EK"
        },
        "matched": {
          "atomic": "0c415dd718e3b3728707d579cf8214f54c2942e964975a5f925e0b82fea644b4",
          "field": "file.hash.sha256",
          "id": "abc123f03",
          "index": "threat-indicators-index-000001",
          "type": "indicator_match_rule"
        }
      }
    ]
  }
}
		
	

Add each enrichment to a nested object under threat.enrichments.*.
The matched object provides context about the indicators this event matched on.