Mimecast Threat Intelligence

Overview

Mimecast's Targeted Threat Protection (TTP) is an advanced security layer that inspects URLs and attachments in real time and detects impersonation attempts. When TTP events occur — a user clicking a suspicious URL, a malicious attachment being sandboxed, or an impersonation attempt being identified — Mimecast logs these as TTP events that feed into threat remediation incidents. This skill covers reading TTP logs, reviewing threat remediation incidents, and using audit events to investigate security events.

Key Concepts

Targeted Threat Protection (TTP)

TTP has three components:

1. URL Protection — Rewrites URLs in emails and checks them at click time against reputation databases. Tracks every URL click attempt, whether blocked or permitted.
2. Attachment Protection — Sandboxes email attachments before delivery. Detects malware, zero-day exploits, and suspicious macros.
3. Impersonation Protection — Detects emails that spoof trusted senders — executives, trusted domains, or known contacts.

Threat Remediation Incidents

When TTP identifies a confirmed threat (e.g. a URL classified as malicious after delivery, or a sandboxed attachment containing malware), Mimecast can create a threat remediation incident — a structured record of the threat and recommended remediation actions, such as removing emails from user mailboxes.

Audit Events

The Mimecast audit log records all administrative actions and significant security events — policy changes, user login events, held message releases, and API operations. Useful for compliance investigations and detecting unauthorized admin activity.

API Patterns

Get TTP Logs

mimecast_get_ttp_logs

Retrieves TTP event logs across URL protection, attachment protection, and impersonation protection.

Parameters:

• type — Log type: url, attachment, or impersonation
• start — Start datetime (ISO 8601)
• end — End datetime (ISO 8601)
• pageToken — Pagination cursor

Example — URL click logs:

{
  "type": "url",
  "start": "2026-03-01T00:00:00Z",
  "end": "2026-03-02T23:59:59Z"
}

Example URL TTP response:

{
  "meta": {
    "status": 200,
    "pagination": {
      "pageSize": 25,
      "totalCount": 18,
      "next": null
    }
  },
  "data": [
    {
      "date": "2026-03-01T14:35:22Z",
      "url": "https://malicious-site.com/payload",
      "action": "block",
      "userEmail": "[email protected]",
      "from": "[email protected]",
      "subject": "Your account needs attention",
      "messageId": "<[email protected]>",
      "scanResult": "malicious",
      "category": "phishing"
    },
    {
      "date": "2026-03-01T09:12:05Z",
      "url": "https://legitimate-site.com/page",
      "action": "allow",
      "userEmail": "[email protected]",
      "from": "[email protected]",
      "subject": "Monthly Update",
      "messageId": "<[email protected]>",
      "scanResult": "clean",
      "category": null
    }
  ]
}

Key fields:

• action — block (URL blocked) or allow (URL permitted)
• scanResult — malicious, suspicious, or clean
• category — Threat category (phishing, malware, spam, etc.)

Example — Attachment TTP response:

{
  "meta": { "status": 200 },
  "data": [
    {
      "date": "2026-03-01T11:20:00Z",
      "filename": "invoice_march.xlsm",
      "result": "malicious",
      "definition": "Macro dropper — Emotet variant",
      "from": "[email protected]",
      "to": "[email protected]",
      "messageId": "<[email protected]>",
      "action": "block"
    }
  ]
}

Example — Impersonation TTP response:

{
  "meta": { "status": 200 },
  "data": [
    {
      "date": "2026-03-01T16:44:00Z",
      "from": "[email protected]",
      "to": "[email protected]",
      "subject": "Urgent Wire Transfer",
      "action": "hold",
      "definition": "Domain lookalike — executive impersonation",
      "similarDomain": "client.com"
    }
  ]
}

Get Threat Remediation Incidents

mimecast_get_threat_incidents

Returns threat remediation incidents — confirmed threats requiring mailbox remediation.

Parameters:

• start — Start datetime (ISO 8601)
• end — End datetime (ISO 8601)
• pageToken — Pagination cursor

Example response:

{
  "meta": { "status": 200 },
  "data": [
    {
      "id": "TRI-20260301-001",
      "created": "2026-03-01T15:00:00Z",
      "type": "url",
      "status": "open",
      "severity": "high",
      "reason": "URL reclassified as malicious post-delivery",
      "url": "https://malicious-site.com/payload",
      "affectedUsers": [
        "[email protected]",
        "[email protected]"
      ],
      "affectedMessages": 4,
      "remediationAction": "remove_from_mailbox",
      "remediationStatus": "pending"
    }
  ]
}

Get Audit Events

mimecast_get_audit_events

Retrieves the Mimecast audit log for administrative and security events.

Parameters:

• start — Start datetime (ISO 8601)
• end — End datetime (ISO 8601)
• category — Event category filter (optional): authentication, policy, message, user
• pageToken — Pagination cursor

Example response:

{
  "meta": { "status": 200 },
  "data": [
    {
      "id": "audit-001",
      "timestamp": "2026-03-01T08:00:00Z",
      "category": "authentication",
      "action": "admin_login",
      "user": "[email protected]",
      "ip": "203.0.113.10",
      "result": "success"
    },
    {
      "id": "audit-002",
      "timestamp": "2026-03-01T08:45:00Z",
      "category": "message",
      "action": "held_message_release",
      "user": "[email protected]",
      "messageId": "<[email protected]>",
      "result": "success"
    }
  ]
}

Common Workflows

Daily Threat Review

1. Call mimecast_get_ttp_logs with type=url for the past 24 hours
2. Filter for action=block and scanResult=malicious — these are confirmed threats
3. Identify users who clicked blocked URLs — they attempted to access malicious content
4. Call mimecast_get_ttp_logs with type=attachment for same period
5. Check for result=malicious — these are blocked malware attachments
6. Call mimecast_get_threat_incidents to see any new post-delivery reclassifications
7. Create PSA tickets for affected users requiring security awareness follow-up

Investigate a Specific Phishing Campaign

1. Identify the phishing domain or URL from a user report
2. Call mimecast_get_ttp_logs with type=url and a broad time range
3. Filter results for the phishing domain across all users
4. Identify all recipients who received the phishing URL
5. Check action field — allow means the URL was not blocked at click time (user may have visited)
6. If users accessed the URL, escalate to credential compromise investigation
7. Call mimecast_find_message to trace all emails containing that domain to understand campaign scope

Detect BEC / Executive Impersonation

1. Call mimecast_get_ttp_logs with type=impersonation for the past 7 days
2. Look for action=allow entries — impersonation attempts that were not blocked
3. Identify sender domains in similarDomain field — these are lookalike domains
4. Cross-reference with mimecast_find_message to confirm if those emails reached inboxes
5. Alert affected executives and implement additional impersonation policy rules

Post-Delivery Threat Remediation

1. Call mimecast_get_threat_incidents to identify open incidents
2. For each incident, note affectedUsers and affectedMessages
3. Review remediationAction — typically remove_from_mailbox
4. Confirm remediationStatus — if pending, Mimecast may require administrator approval in the console
5. Notify affected users that suspicious emails have been or will be removed from their mailboxes

Compliance Audit Investigation

1. Call mimecast_get_audit_events with category=authentication for a time range
2. Review admin logins — unexpected IP addresses or off-hours access are suspicious
3. Call with category=policy to identify configuration changes
4. Document findings with timestamps and actor email addresses for the compliance report

Error Handling

No TTP Data Returned

Cause: TTP is not enabled for the tenant, or the date range has no events. Solution: Verify TTP is licensed and enabled in the Mimecast Administration Console under Services > Targeted Threat Protection.

Incident Remediation Status Stuck at Pending

Cause: Threat remediation incidents may require manual approval in the Mimecast console depending on the tenant's remediation policy. Solution: Log into the Mimecast Administration Console and navigate to Security > Threat Remediation to manually approve pending remediations.

Audit Log Returns Empty for Recent Events

Cause: Audit log propagation can have a short delay (up to 15 minutes). Solution: Retry with a slight delay; also verify the correct region is configured.

Best Practices

• Check TTP URL logs daily — blocked clicks indicate active threats targeting your users
• action=allow URL entries where scanResult=malicious mean Mimecast reclassified the URL after the click — treat these as confirmed user exposures
• Always cross-reference TTP attachment detections with mimecast_find_message to confirm whether other users received the same attachment
• Impersonation TTP logs with action=allow are the most dangerous — the email reached the inbox despite being flagged
• Use audit event logs to detect unauthorized admin activity, especially after a security incident
• Export TTP logs weekly for trend analysis — increasing block counts may indicate a targeted campaign

Related Skills

• api-patterns - Authentication, pagination, error codes
• message-tracking - Trace and manage specific messages
• queue-management - Delivery queue monitoring