Mimecast Email Security

Overview

A secure email gateway to block spam, viruses, and malware.

• Vendor: Mimecast
• Supported environment: Cloud
• Detection based on: Telemetry
• Supported application or feature: Email gateway

Warning

Important note - This format is currently in beta. We highly value your feedback to improve its performance.

Supported datasets

This integration can collect the following datasets from Mimecast:

• Attachment protect
• Antivirus
• Delivery
• Impersonation protect
• Internal email protect
• Journal
• Process
• Receipt
• Spam
• URL protect

High-Level Architecture Diagram

• Type of integration: PULL by Sekoia.io
• Schema

Specification

Prerequisites

• Permissions:
  • The Mimecast administrator must be assigned a Role with the following criteria.
    • Read and Edit API Application Permissions under the Service Menu.
    • Security Permissions setting must permit the Management of Application Roles.
  • The generated API key must be a Mimecast Administrator with at least the Security Events and Data Retrieval | Threat and Security Events (SIEM) and Threat and security statistics | Read permission.

Transport Protocol/Method

• Direct HTTP

Logs details

• Supported functionalities: See section Overview
• Supported type(s) of structure: JSON
• Supported verbosity level: Informational

Note

Log levels are based on the taxonomy of RFC5424. Adapt according to the terminology used by the editor.

Step-by-Step Configuration Procedure

Instructions on the 3rd Party Solution

Create API credentials

1. Login to Mimecast Administration Console
2. Navigate to Account > Roles > New Role
3. Name the role as you wish, for instance "Sekoia"
4. Add the following roles under the section called Security Events and Data Retrieval:
   • Threat and security svents (SIEM) with READ permission,
   • Threat and security statistics with READ permission.
5. Navigate to Services | API and Platform Integrations
6. Locate the following Mimecast API 2.0 tile and click on Generate Keys.
7. After reading the Terms & Conditions, complete the I accept check box to enable the Next button to progress onto the next step.
8. Complete the Application Details section by providing:
   • Application Name: Select SIEM Integration,
   • Description (Optional),
   • Integration Partner (Optional),
   • Products: Select all products,
   • Role: Select the "Sekoia" role created above.
9. Complete the Notifications section by providing:
   • Technical Point of Contact: Write the name of the administrator to be contacted if you encounter any issue with the API,
   • Email : Write the administrator's email.
10. Validate the form and Click on Add and Generate Keys
11. The wizard completes and displays a pop-up window including your Client ID and Client Secret key data.

Activate logging

1. Login to Mimecast Administration Console
2. Navigate to Account > Account Settings > Enhanced Logging
3. Select the Enhanced Logging option that you want:

Instruction on Sekoia

Create your intake

1. Navigate to the intake page and create a new intake using the Mimecast Email Security integration.
2. If you do not already have one, create an account by entering your Client ID and Client Secret. If you have an existing account, simply select it from the list.
3. Configure the settings by choosing your preferred Chunk Size and Frequency.
4. Copy the newly created Intake Key for use in your setup.

Note

Mimecast provides events in batches every 15 minutes. In order to comply with the Mimecast ratelimiting (50 calls per 15 minutes), the default frequency is set to 8 minutes.

Enjoy your events on the Events page

Raw Events Samples

In this section, you will find examples of raw logs as generated natively by the source. These examples are provided to help integrators understand the data format before ingestion into Sekoia.io. It is crucial for setting up the correct parsing stages and ensuring that all relevant information is captured.

test_journaltest_processtest_process_with_attachmenttest_process_with_multiple_attachmentstest_receipt

{
    "aggregateId": "vC80NNxvOWKkBPnzSs04FA_1715699686",
    "processingId": "PGZfGuxEAu_kE-nGy1sjThBr5EYbm1ZcDKg-vXbRHLA_1715699686",
    "accountId": "CDE22A102",
    "timestamp": 1715699697146,
    "senderEnvelope": "newsletter@stub.com",
    "recipients": "neo@gmail.fr",
    "direction": "Inbound",
    "type": "journal",
    "subtype": null,
    "_offset": 105760,
    "_partition": 137
}

{
    "aggregateId": "J5JwSy0HNvG7AvCg1sgDvQ_1715708284",
    "processingId": "hP5f7mBanAVkWJWfh4vYvca3zOi9I3jROBmH3Z_Kysk_1715708284",
    "accountId": "CDE22A102",
    "action": "Hld",
    "timestamp": 1715708287466,
    "senderEnvelope": "john.doe015@gmail.com",
    "messageId": "<CAF7=BmDb+6qHo+J5EB9oH+S4ncJOfEMsUYAEirX4MRZRJX+esw@mail.gmail.com>",
    "subject": "Moderate",
    "holdReason": "Spm",
    "totalSizeAttachments": "0",
    "numberAttachments": "0",
    "attachments": null,
    "emailSize": "3466",
    "type": "process",
    "subtype": "Hld",
    "_offset": 105825,
    "_partition": 137
}

{
    "processingId": "processingId",
    "aggregateId": "aggregateId",
    "numberAttachments": "2",
    "attachments": "tpsreport.doc",
    "subject": "siem_process - email subject line",
    "senderEnvelope": "auser@mimecast.com",
    "messageId": "messageId",
    "eventType": "process",
    "accountId": "C0A0",
    "action": "Allow",
    "holdReason": null,
    "subType": "Allow",
    "totalSizeAttachments": "642",
    "timestamp": 1689685338609,
    "emailSize": "56422"
}

{
    "aggregateId": "aggId1",
    "processingId": "AAA_123",
    "accountId": "ACCOUNT1",
    "action": "Acc",
    "timestamp": 1733997069148,
    "senderEnvelope": "johndoe@gmail.com",
    "messageId": "1@mail.gmail.com>",
    "subject": "TEST SEKOIA",
    "holdReason": null,
    "totalSizeAttachments": "183525",
    "numberAttachments": "0",
    "attachments": "\"~WRD0601.jpg\", \"image001.png\", \"image002.jpg\", \"image003.png\", \"image004.jpg\", \"image005.jpg\", \"image006.png\", \"image007.jpg\", \"image008.png\", \"image009.png\", \"image010.png\", \"image011.jpg\", \"image012.png\", \"image013.jpg\", \"image014.jpg\"",
    "emailSize": "204490",
    "type": "process",
    "subtype": "Acc",
    "_offset": 292955,
    "_partition": 137
}

{
    "aggregateId": "J5JwSy0HNvG7AvCg1sgDvQ_1715708284",
    "processingId": "hP5f7mBanAVkWJWfh4vYvca3zOi9I3jROBmH3Z_Kysk_1715708284",
    "accountId": "CDE22A102",
    "timestamp": 1715708286579,
    "action": "Acc",
    "senderEnvelope": "john.doe@gmail.com",
    "messageId": "<CAF7=BmDb+6qHo+J5EB9oH+S4ncJOfEMsUYAAarX4MRZRJX+esw@mail.gmail.com>",
    "subject": "Moderate",
    "recipients": "admin@mcfr2.pro",
    "senderIp": "209.123.123.123",
    "rejectionType": null,
    "rejectionCode": null,
    "direction": "Inbound",
    "numberAttachments": "0",
    "senderHeader": "john.doe@gmail.com",
    "rejectionInfo": null,
    "tlsVersion": "TLSv1.3",
    "tlsCipher": "TLS_AES_256_GCM_SHA384",
    "spamInfo": "[]",
    "spamProcessingDetail": "{\"spf\":{\"allow\":true,\"info\":\"ALLOW\"},\"dkim\":{\"allow\":true,\"info\":\"ALLOW\"},\"dmarc\":{\"allow\":true,\"info\":\"ALLOW\"}}",
    "virusFound": null,
    "type": "receipt",
    "subtype": "Acc",
    "_offset": 105826,
    "_partition": 137
}

Detection section

The following section provides information for those who wish to learn more about the detection capabilities enabled by collecting this intake. It includes details about the built-in rule catalog, event categories, and ECS fields extracted from raw events. This is essential for users aiming to create custom detection rules, perform hunting activities, or pivot in the events page.

Related Built-in Rules

The following Sekoia.io built-in rules match the intake Mimecast Email Security [BETA]. This documentation is updated automatically and is based solely on the fields used by the intake which are checked against our rules. This means that some rules will be listed but might not be relevant with the intake.

SEKOIA.IO x Mimecast Email Security [BETA] on ATT&CK Navigator

Burp Suite Tool Detected

Burp Suite is a cybersecurity tool. When used as a proxy service, its purpose is to intercept packets and modify them to send them to the server. Burp Collaborator is a network service that Burp Suite uses to help discover many kinds of vulnerabilities (vulnerabilities scanner).

• Effort: intermediate

CVE-2020-0688 Microsoft Exchange Server Exploit

Detects the exploitation of CVE-2020-0688. The POC exploit a .NET serialization vulnerability in the Exchange Control Panel (ECP) web page. The vulnerability is due to Microsoft Exchange Server not randomizing the keys on a per-installation basis resulting in them using the same validationKey and decryptionKey values. With knowledge of these, values an attacker can craft a special viewstate to use an OS command to be executed by NT_AUTHORITY\SYSTEM using .NET deserialization. To exploit this vulnerability, an attacker needs to leverage the credentials of an account it had already compromised to authenticate to OWA.

• Effort: elementary

CVE-2020-17530 Apache Struts RCE

Detects the exploitation of the Apache Struts RCE vulnerability (CVE-2020-17530).

• Effort: intermediate

CVE-2021-20021 SonicWall Unauthenticated Administrator Access

Detects the exploitation of SonicWall Unauthenticated Admin Access.

• Effort: advanced

CVE-2021-20023 SonicWall Arbitrary File Read

Detects Arbitrary File Read, which can be used with other vulnerabilities as a mean to obtain outputs generated by attackers, or sensitive data.

• Effort: advanced

CVE-2021-22893 Pulse Connect Secure RCE Vulnerability

Detects potential exploitation of the authentication by-pass vulnerability that can allow an unauthenticated user to perform remote arbitrary file execution on the Pulse Connect Secure gateway. It is highly recommended to apply the Pulse Secure mitigations and seach for indicators of compromise on affected servers if you are in doubt over the integrity of your Pulse Connect Secure product.

• Effort: intermediate

Cryptomining

Detection of domain names potentially related to cryptomining activities.

• Effort: master

Detect requests to Konni C2 servers

This rule detects requests to Konni C2 servers. These patterns come from an analysis done in 2022, September.

• Effort: elementary

Discord Suspicious Download

Discord is a messaging application. It allows users to create their own communities to share messages and attachments. Those attachments have little to no overview and can be downloaded by almost anyone, which has been abused by attackers to host malicious payloads.

• Effort: intermediate

Download Files From Suspicious TLDs

Detects download of certain file types from hosts in suspicious TLDs

• Effort: master

Dynamic DNS Contacted

Detect communication with dynamic dns domain. This kind of domain is often used by attackers. This rule can trigger false positive in non-controlled environment because dynamic dns is not always malicious.

• Effort: master

Exfiltration Domain

Detects traffic toward a domain flagged as a possible exfiltration vector.

• Effort: master

Koadic MSHTML Command

Detects Koadic payload using MSHTML module

• Effort: intermediate

Possible Malicious File Double Extension

Detects request to potential malicious file with double extension

• Effort: elementary

ProxyShell Microsoft Exchange Suspicious Paths

Detects suspicious calls to Microsoft Exchange resources, in locations related to webshells observed in campaigns using this vulnerability.

• Effort: elementary

Raccoon Stealer 2.0 Legitimate Third-Party DLL Download URL

Detects Raccoon Stealer 2.0 malware downloading legitimate third-party DLLs from its C2 server. These legitimate DLLs are used by the information stealer to collect data on the compromised hosts.

• Effort: elementary

Remote Access Tool Domain

Detects traffic toward a domain flagged as a Remote Administration Tool (RAT).

• Effort: master

SEKOIA.IO Intelligence Feed

Detect threats based on indicators of compromise (IOCs) collected by SEKOIA's Threat and Detection Research team.

• Effort: elementary

Sekoia.io EICAR Detection

Detects observables in Sekoia.io CTI tagged as EICAR, which are fake samples meant to test detection.

• Effort: master

Suspicious Download Links From Legitimate Services

Detects users clicking on Google docs links to download suspicious files. This technique was used a lot by Bazar Loader in the past.

• Effort: intermediate

Suspicious TOR Gateway

Detects suspicious TOR gateways. Gateways are often used by the victim to pay and decrypt the encrypted files without installing TOR. Tor intercepts the network traffic from one or more apps on user’s computer, usually the user web browser, and shuffles it through a number of randomly-chosen computers before passing it on to its destination. This disguises user location, and makes it harder for servers to pick him/her out on repeat visits, or to tie together separate visits to different sites, this making tracking and surveillance more difficult. Before a network packet starts its journey, user’s computer chooses a random list of relays and repeatedly encrypts the data in multiple layers, like an onion. Each relay knows only enough to strip off the outermost layer of encryption, before passing what’s left on to the next relay in the list.

• Effort: advanced

Suspicious URI Used In A Lazarus Campaign

Detects suspicious requests to a specific URI, usually on an .asp page. The website is often compromised.

• Effort: intermediate

TOR Usage Generic Rule

Detects TOR usage globally, whether the IP is a destination or source. TOR is short for The Onion Router, and it gets its name from how it works. TOR intercepts the network traffic from one or more apps on user’s computer, usually the user web browser, and shuffles it through a number of randomly-chosen computers before passing it on to its destination. This disguises user location, and makes it harder for servers to pick him/her out on repeat visits, or to tie together separate visits to different sites, this making tracking and surveillance more difficult. Before a network packet starts its journey, user’s computer chooses a random list of relays and repeatedly encrypts the data in multiple layers, like an onion. Each relay knows only enough to strip off the outermost layer of encryption, before passing what’s left on to the next relay in the list.

• Effort: master

Event Categories

The following table lists the data source offered by this integration.

Data Source	Description
Email gateway	Inbound, outbound and internal logs for messages

In details, the following table denotes the type of events produced by this integration.

Name	Values
Kind	``
Category	email
Type	denied, info

Transformed Events Samples after Ingestion

This section demonstrates how the raw logs will be transformed by our parsers. It shows the extracted fields that will be available for use in the built-in detection rules and hunting activities in the events page. Understanding these transformations is essential for analysts to create effective detection mechanisms with custom detection rules and to leverage the full potential of the collected data.

test_journal.jsontest_process.jsontest_process_with_attachment.jsontest_process_with_multiple_attachments.jsontest_receipt.json

{
    "message": "{\"aggregateId\": \"vC80NNxvOWKkBPnzSs04FA_1715699686\", \"processingId\": \"PGZfGuxEAu_kE-nGy1sjThBr5EYbm1ZcDKg-vXbRHLA_1715699686\", \"accountId\": \"CDE22A102\", \"timestamp\": 1715699697146, \"senderEnvelope\": \"newsletter@stub.com\", \"recipients\": \"neo@gmail.fr\", \"direction\": \"Inbound\", \"type\": \"journal\", \"subtype\": null, \"_offset\": 105760, \"_partition\": 137}",
    "event": {
        "category": [
            "email"
        ],
        "dataset": "journal",
        "provider": "Mimecast",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2024-05-14T15:14:57.146000Z",
    "email": {
        "direction": "Inbound",
        "from": {
            "address": [
                "newsletter@stub.com"
            ]
        },
        "to": {
            "address": [
                "neo@gmail.fr"
            ]
        }
    },
    "mimecast": {
        "siem": {
            "aggregate_id": "vC80NNxvOWKkBPnzSs04FA_1715699686",
            "processing_id": "PGZfGuxEAu_kE-nGy1sjThBr5EYbm1ZcDKg-vXbRHLA_1715699686"
        }
    }
}

{
    "message": "{\"aggregateId\": \"J5JwSy0HNvG7AvCg1sgDvQ_1715708284\", \"processingId\": \"hP5f7mBanAVkWJWfh4vYvca3zOi9I3jROBmH3Z_Kysk_1715708284\", \"accountId\": \"CDE22A102\", \"action\": \"Hld\", \"timestamp\": 1715708287466, \"senderEnvelope\": \"john.doe015@gmail.com\", \"messageId\": \"<CAF7=BmDb+6qHo+J5EB9oH+S4ncJOfEMsUYAEirX4MRZRJX+esw@mail.gmail.com>\", \"subject\": \"Moderate\", \"holdReason\": \"Spm\", \"totalSizeAttachments\": \"0\", \"numberAttachments\": \"0\", \"attachments\": null, \"emailSize\": \"3466\", \"type\": \"process\", \"subtype\": \"Hld\", \"_offset\": 105825, \"_partition\": 137}",
    "event": {
        "action": "Hld",
        "category": [
            "email"
        ],
        "dataset": "process",
        "provider": "Mimecast",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2024-05-14T17:38:07.466000Z",
    "email": {
        "from": {
            "address": [
                "john.doe015@gmail.com"
            ]
        },
        "message_id": "CAF7=BmDb+6qHo+J5EB9oH+S4ncJOfEMsUYAEirX4MRZRJX+esw@mail.gmail.com",
        "to": {
            "address": [
                "null"
            ]
        }
    },
    "mimecast": {
        "siem": {
            "aggregate_id": "J5JwSy0HNvG7AvCg1sgDvQ_1715708284",
            "hold_reason": "Spm",
            "processing_id": "hP5f7mBanAVkWJWfh4vYvca3zOi9I3jROBmH3Z_Kysk_1715708284"
        }
    }
}

{
    "message": "{\"processingId\": \"processingId\", \"aggregateId\": \"aggregateId\", \"numberAttachments\": \"2\", \"attachments\": \"tpsreport.doc\", \"subject\": \"siem_process - email subject line\", \"senderEnvelope\": \"auser@mimecast.com\", \"messageId\": \"messageId\", \"eventType\": \"process\", \"accountId\": \"C0A0\", \"action\": \"Allow\", \"holdReason\": null, \"subType\": \"Allow\", \"totalSizeAttachments\": \"642\", \"timestamp\": 1689685338609, \"emailSize\": \"56422\"}",
    "event": {
        "action": "Allow",
        "category": [
            "email"
        ],
        "dataset": "process",
        "provider": "Mimecast",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2023-07-18T13:02:18.609000Z",
    "email": {
        "attachments": [
            {
                "file": {
                    "name": "tpsreport.doc"
                }
            }
        ],
        "from": {
            "address": [
                "auser@mimecast.com"
            ]
        },
        "message_id": "messageId",
        "to": {
            "address": [
                "null"
            ]
        }
    },
    "mimecast": {
        "siem": {
            "aggregate_id": "aggregateId",
            "processing_id": "processingId"
        }
    }
}

{
    "message": "{\"aggregateId\": \"aggId1\", \"processingId\": \"AAA_123\", \"accountId\": \"ACCOUNT1\", \"action\": \"Acc\", \"timestamp\": 1733997069148, \"senderEnvelope\": \"johndoe@gmail.com\", \"messageId\": \"1@mail.gmail.com>\", \"subject\": \"TEST SEKOIA\", \"holdReason\": null, \"totalSizeAttachments\": \"183525\", \"numberAttachments\": \"0\", \"attachments\": \"\\\"~WRD0601.jpg\\\", \\\"image001.png\\\", \\\"image002.jpg\\\", \\\"image003.png\\\", \\\"image004.jpg\\\", \\\"image005.jpg\\\", \\\"image006.png\\\", \\\"image007.jpg\\\", \\\"image008.png\\\", \\\"image009.png\\\", \\\"image010.png\\\", \\\"image011.jpg\\\", \\\"image012.png\\\", \\\"image013.jpg\\\", \\\"image014.jpg\\\"\", \"emailSize\": \"204490\", \"type\": \"process\", \"subtype\": \"Acc\", \"_offset\": 292955, \"_partition\": 137}",
    "event": {
        "action": "Acc",
        "category": [
            "email"
        ],
        "dataset": "process",
        "provider": "Mimecast",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2024-12-12T09:51:09.148000Z",
    "email": {
        "attachments": [
            {
                "file": {
                    "name": "~WRD0601.jpg"
                }
            },
            {
                "file": {
                    "name": "image001.png"
                }
            },
            {
                "file": {
                    "name": "image002.jpg"
                }
            },
            {
                "file": {
                    "name": "image003.png"
                }
            },
            {
                "file": {
                    "name": "image004.jpg"
                }
            },
            {
                "file": {
                    "name": "image005.jpg"
                }
            },
            {
                "file": {
                    "name": "image006.png"
                }
            },
            {
                "file": {
                    "name": "image007.jpg"
                }
            },
            {
                "file": {
                    "name": "image008.png"
                }
            },
            {
                "file": {
                    "name": "image009.png"
                }
            },
            {
                "file": {
                    "name": "image010.png"
                }
            },
            {
                "file": {
                    "name": "image011.jpg"
                }
            },
            {
                "file": {
                    "name": "image012.png"
                }
            },
            {
                "file": {
                    "name": "image013.jpg"
                }
            },
            {
                "file": {
                    "name": "image014.jpg"
                }
            }
        ],
        "from": {
            "address": [
                "johndoe@gmail.com"
            ]
        },
        "message_id": "1@mail.gmail.com",
        "to": {
            "address": [
                "null"
            ]
        }
    },
    "mimecast": {
        "siem": {
            "aggregate_id": "aggId1",
            "processing_id": "AAA_123"
        }
    }
}

{
    "message": "{\"aggregateId\": \"J5JwSy0HNvG7AvCg1sgDvQ_1715708284\", \"processingId\": \"hP5f7mBanAVkWJWfh4vYvca3zOi9I3jROBmH3Z_Kysk_1715708284\", \"accountId\": \"CDE22A102\", \"timestamp\": 1715708286579, \"action\": \"Acc\", \"senderEnvelope\": \"john.doe@gmail.com\", \"messageId\": \"<CAF7=BmDb+6qHo+J5EB9oH+S4ncJOfEMsUYAAarX4MRZRJX+esw@mail.gmail.com>\", \"subject\": \"Moderate\", \"recipients\": \"admin@mcfr2.pro\", \"senderIp\": \"209.123.123.123\", \"rejectionType\": null, \"rejectionCode\": null, \"direction\": \"Inbound\", \"numberAttachments\": \"0\", \"senderHeader\": \"john.doe@gmail.com\", \"rejectionInfo\": null, \"tlsVersion\": \"TLSv1.3\", \"tlsCipher\": \"TLS_AES_256_GCM_SHA384\", \"spamInfo\": \"[]\", \"spamProcessingDetail\": \"{\\\"spf\\\":{\\\"allow\\\":true,\\\"info\\\":\\\"ALLOW\\\"},\\\"dkim\\\":{\\\"allow\\\":true,\\\"info\\\":\\\"ALLOW\\\"},\\\"dmarc\\\":{\\\"allow\\\":true,\\\"info\\\":\\\"ALLOW\\\"}}\", \"virusFound\": null, \"type\": \"receipt\", \"subtype\": \"Acc\", \"_offset\": 105826, \"_partition\": 137}",
    "event": {
        "action": "Acc",
        "category": [
            "email"
        ],
        "dataset": "receipt",
        "provider": "Mimecast",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2024-05-14T17:38:06.579000Z",
    "email": {
        "direction": "Inbound",
        "from": {
            "address": [
                "john.doe@gmail.com"
            ]
        },
        "message_id": "CAF7=BmDb+6qHo+J5EB9oH+S4ncJOfEMsUYAAarX4MRZRJX+esw@mail.gmail.com",
        "to": {
            "address": [
                "admin@mcfr2.pro"
            ]
        }
    },
    "mimecast": {
        "siem": {
            "aggregate_id": "J5JwSy0HNvG7AvCg1sgDvQ_1715708284",
            "processing_id": "hP5f7mBanAVkWJWfh4vYvca3zOi9I3jROBmH3Z_Kysk_1715708284"
        }
    },
    "related": {
        "ip": [
            "209.123.123.123"
        ]
    },
    "source": {
        "address": "209.123.123.123",
        "ip": "209.123.123.123"
    }
}

Extracted Fields

The following table lists the fields that are extracted, normalized under the ECS format, analyzed and indexed by the parser. It should be noted that infered fields are not listed.

Name	Type	Description
@timestamp	date	Date/time when the event originated.
destination.ip	ip	IP address of the destination.
email.attachments	nested	List of objects describing the attachments.
email.direction	keyword	Direction of the message.
email.from.address	keyword	The sender's email address.
email.message_id	wildcard	Value from the Message-ID header.
email.to.address	keyword	Email address of recipient
event.action	keyword	The action captured by the event.
event.category	keyword	Event category. The second categorization field in the hierarchy.
event.dataset	keyword	Name of the dataset.
event.provider	keyword	Source of the event.
event.type	keyword	Event type. The third categorization field in the hierarchy.
mimecast.siem.aggregate_id	keyword	Unique identifier that allows you to correlate/group related events.
mimecast.siem.delivered	boolean	If the email was delivered successfully or not.
mimecast.siem.delivery_errors	keyword	Information about any errors that occurred on the delivery attempt.
mimecast.siem.hold_reason	keyword	The reason the email was held for review (quarantined), if applicable.
mimecast.siem.processing_id	keyword	Unique identifier that allows you to correlate/group related events.
mimecast.siem.rejection.code	number	The rejection code issued if the email was rejected at the receipt stage.
mimecast.siem.rejection.info	keyword	The rejection information if the email was rejected at the receipt stage.
mimecast.siem.rejection.type	keyword	The rejection type if the email was rejected at the receipt stage.
mimecast.siem.virus_found	keyword	The name of the virus found on the email, if applicable.
source.ip	ip	IP address of the source.

For more information on the Intake Format, please find the code of the Parser, Smart Descriptions, and Supported Events here.

Further Readings

• Create API 2.0 Application