AN1107: Analytic 1107
Detection of ApplicationImpersonation role assignment or delegated mailbox access to service principals or rarely used users, especially outside of normal hours or geographic norms.
Analyst context for executives and security teams
This analytic matters because mailbox impersonation or delegated mailbox access granted to service principals or rarely used users can create quiet, high-value access to business communications. For executives and security leaders, the decision point is whether identity, mail, and audit teams can prove who is allowed to impersonate or access mailboxes, when those grants changed, and whether the activity fits normal business patterns such as working hours and expected geographies.
Executive priority
Prioritize this as an identity and Office Suite governance issue, not only a SOC alert. ApplicationImpersonation and delegated mailbox access can affect sensitive communications, legal/audit evidence, executive mail, and incident scope decisions. Leaders should ask whether privileged mailbox access is reviewed, whether service principals have clear business owners, and whether audit evidence exists to support investigations and compliance inquiries.
Technical view
For SOC, detection engineering, and IR teams, validate monitoring for role assignments and delegated mailbox permissions involving service principals or rarely used users in the Office Suite environment. Since the ATT&CK object provides no detailed detection logic and no tactic mapping, teams should build local baselines around normal administrative changes, expected service principal behavior, normal access times, and expected geographies. Investigations should correlate permission changes with subsequent mailbox access and identity sign-in context where available.
Likely telemetry
- Office Suite administrative audit logs for ApplicationImpersonation role assignment changes
- Mailbox permission and delegated access change logs
- Service principal identity and permission inventory
- User and service principal sign-in logs, including time and geography where available
- Mailbox access audit events
Detection direction
- Validate alerting for ApplicationImpersonation assignments to service principals and rarely used users.
- Validate alerting for delegated mailbox access grants that deviate from known administrative patterns.
- Tune detections using local baselines for normal business hours, expected administrator accounts, approved service principals, and expected geographies.
- Reduce false positives by maintaining an authoritative inventory of approved service principals, mailbox automation, and sanctioned delegated access.
- Look for correlation between new or unusual permission grants and subsequent mailbox access activity.
Mitigation priorities
- Maintain ownership and justification records for service principals with mailbox-related privileges.
- Review and remove unnecessary ApplicationImpersonation and delegated mailbox access assignments.
- Apply least privilege to mailbox administration and delegated access processes.
- Require periodic access reviews for privileged mailbox roles and rarely used accounts.
- Ensure Office Suite audit logging and retention are sufficient for incident response and compliance evidence.
Analyst notes and limits
This object is a MITRE ATT&CK detection analytic, not a full technique description. The strongest practical use is as a validation prompt: confirm that identity and mail teams can see, explain, and investigate privileged mailbox access changes involving service principals and rarely used users.
The supplied ATT&CK fields do not include official detection logic, tactics, relationships, procedures, or mitigations. Recommendations are therefore limited to conservative defensive validation based on the official description, Office Suite platform, and external reference.
Analytic 1107
Detection of ApplicationImpersonation role assignment or delegated mailbox access to service principals or rarely used users, especially outside of normal hours or geographic norms.
How security teams should use this page
Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.
All related ATT&CK context
No relationships are available in the current normalized data for this object.
Object version and sync metadata
The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates .
Imported snapshots across ATT&CK releases (1)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.1 | 1.0 | Current bundle | f16e6d3d660c… |
Mirrored ATT&CK source object
The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.
External references and citations
MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.
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[1]
mitre-attack AN1107Open source URL
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