1. Purpose
The Security Event Register is the central record used to track information security events from initial detection or reporting through assessment, classification, response, and closure.
It provides the organization with a consistent method to:
- Record security events
- Assign unique event IDs
- Track the source and affected assets
- Record initial and final assessments
- Document evidence
- Classify events consistently
- Identify events that require escalation
- Link security events to formal incidents
- Track corrective actions
- Identify recurring security weaknesses
- Support management review and continual improvement
- Provide audit evidence of security event monitoring and assessment
The register should contain both events that become formal incidents and events that are assessed and closed without becoming incidents.
2. What Is a Security Event?
A security event is an observable occurrence that may have relevance to information security.
Examples include:
- Failed login attempts
- Suspicious authentication
- Phishing email
- Malware detection
- Unexpected cloud activity
- Vulnerability detection
- Unauthorized software
- Security configuration weakness
- Unexpected privilege change
- Suspicious data access
- Security monitoring alert
- Lost device
- Supplier security notification
- Policy violation
- Possible data exposure
Not every security event is a security incident.
For example:
Blocked phishing email → Security Event
Employee enters credentials into phishing website → Suspected Incident
Attacker successfully uses stolen credentials → Confirmed Incident
The register should preserve this distinction.
3. Security Event Lifecycle
The standard lifecycle is:
Detect → Report → Record → Validate → Assess → Classify → Escalate → Respond → Monitor → Correct → Reassess → Close
Where required:
Security Event → Security Incident → Incident Response → Investigation → Recovery → Closure
4. Master Security Event Register
The following fields can be maintained in a spreadsheet, GRC platform, ticketing system, or security-management platform.
| Field | Description |
|---|---|
| Event ID | Unique identifier |
| Date Reported | Date event was reported |
| Time Reported | Time event was reported |
| Event Date/Time | When event occurred, if known |
| Source | Employee, monitoring, supplier, customer, audit, etc. |
| Event Title | Short description |
| Event Category | Phishing, access, malware, cloud, vulnerability, etc. |
| Reporter | Person/system reporting the event |
| Affected Asset | System, device, application, cloud resource, etc. |
| Affected Information | Data potentially involved |
| Business Process | Business process affected |
| Environment | Production / Development / Test |
| Description | Factual description |
| Evidence Reference | Evidence or supporting record |
| Validation Status | Pending / Validated / Not Validated |
| Confidentiality Impact | None / Low / Medium / High / Unknown |
| Integrity Impact | None / Low / Medium / High / Unknown |
| Availability Impact | None / Low / Medium / High / Unknown |
| Customer Impact | None / Possible / Confirmed / Unknown |
| Personal Data Impact | None / Possible / Confirmed / Unknown |
| Business Impact | None / Low / Medium / High / Critical |
| Scope | Isolated / Limited / Broad / Widespread / Unknown |
| Attacker Activity | None / Attempted / Suspicious / Confirmed / Active |
| Persistence | None / Possible / Suspected / Confirmed / Active |
| Classification | CE-0 to CE-5 |
| Severity | SEV-1 to SEV-4, where applicable |
| Escalation Required | Yes / No |
| Escalated To | Person/team |
| Incident Created | Yes / No |
| Incident ID | Related incident ID |
| Response Action | Action taken |
| Corrective Action | Required improvement |
| Action Owner | Responsible person |
| Target Date | Corrective action deadline |
| Status | Open / Investigating / Monitoring / Closed |
| Reassessment Date | Last reassessment |
| Residual Risk | Remaining risk |
| Closure Date | Date closed |
| Closed By | Authorized person |
| Evidence Location | Evidence repository/reference |
5. Event ID Convention
Each event should have a unique identifier.
Example:
SE-2026-0001
Where:
- SE = Security Event
- 2026 = Year
- 0001 = Sequential event number
Examples:
- SE-2026-0001
- SE-2026-0002
- SE-2026-0003
If the event becomes an incident, create or link a separate incident identifier.
Example:
Security Event: SE-2026-0042
Incident: INC-2026-0017
This preserves the history from the original observation through formal incident response.
6. Event Status
Use consistent status values.
| Status | Meaning |
|---|---|
| New | Event has been reported but not yet assessed |
| Validating | Security/IT team is validating the event |
| Assessed | Initial assessment completed |
| Investigating | Additional investigation required |
| Escalated | Event has been escalated |
| Incident Created | Formal incident record created |
| Monitoring | Event does not currently require incident response but requires monitoring |
| Corrective Action | Security weakness or improvement identified |
| Awaiting Information | Additional information required |
| Closed | Assessment and required actions completed |
| Reopened | New information requires reassessment |
7. Event Source
Record how the event was identified.
| Source | Examples |
|---|---|
| Employee | Employee reports suspicious email |
| Security Monitoring | SIEM/EDR/cloud alert |
| IT Team | IT identifies unusual activity |
| Security Team | Security review identifies event |
| Customer | Customer reports suspicious activity |
| Supplier | Supplier reports security issue |
| Audit | Internal/external audit identifies weakness |
| Vulnerability Assessment | Scanner identifies vulnerability |
| Penetration Test | Testing identifies security weakness |
| Management | Management identifies security concern |
| Automated System | Security automation |
| Threat Intelligence | External intelligence |
| Other | Other source |
8. Event Categories
Use standardized categories to support trend analysis.
Identity and Access
- Failed authentication
- Suspicious login
- MFA event
- Password compromise
- Privilege escalation
- Unauthorized access
- Account compromise
Email and Social Engineering
- Phishing
- Spear phishing
- Business email compromise
- Malicious attachment
- Malicious link
Malware
- Malware detection
- Ransomware
- Trojan
- Endpoint compromise
- Suspicious executable
Cloud Security
- Unexpected IAM activity
- Public cloud resource
- Unauthorized resource
- Security-group change
- Cloud credential exposure
- Cloud configuration change
Data Security
- Data exposure
- Unauthorized download
- Incorrect disclosure
- Data transfer
- Possible data breach
Application and Development
- Application vulnerability
- Source-code access
- CI/CD anomaly
- API security event
- Unauthorized deployment
Infrastructure and Network
- Network anomaly
- Firewall change
- Availability event
- Suspicious connection
- Unauthorized device
Supplier / Third Party
- Supplier security alert
- Supplier breach
- Subprocessor issue
- Third-party vulnerability
Governance
- Policy violation
- Security control failure
- Security weakness
- Audit finding
- Compliance issue
9. Initial Event Record
For each new event, capture the following minimum information:
| Field | Example |
|---|---|
| Event ID | SE-2026-0042 |
| Date/Time | 28 September 2026, 10:35 IST |
| Source | Security Monitoring |
| Category | Cloud Security |
| Title | Unexpected AWS IAM Role Creation |
| Reporter | AWS Security Monitoring |
| Asset | AWS Production Account |
| Information | Customer application environment |
| Description | New IAM role created outside approved change window |
| Initial Status | Validating |
| Evidence | CloudTrail Event ID |
| Initial Impact | Unknown |
| Assigned To | Security Lead |
10. Validation Record
Before determining that an event is an incident, validate the activity where practical.
Validation Questions
- Did the event actually occur?
- Is the activity legitimate?
- Was it authorized?
- Was there an approved change?
- Is the account/user legitimate?
- Is the system functioning as expected?
- Is the alert a false positive?
- Is there evidence of unauthorized activity?
- Could information have been accessed?
- Could the event represent a security weakness?
- Is additional investigation required?
Validation Result
- False Positive
- Legitimate Activity
- Routine Security Event
- Security Weakness
- Suspected Incident
- Confirmed Incident
- Major/Critical Incident
- Unable to Determine
11. Impact Assessment
The assessment should consider at least the following dimensions.
Confidentiality
Could unauthorized persons access, disclose, or obtain information?
Integrity
Could information, code, configuration, or systems be modified?
Availability
Could services or systems become unavailable?
Customer Impact
Could customers or customer services be affected?
Information Impact
Could the event involve:
- Personal data
- Financial information
- Confidential information
- Customer information
- Credentials
- Source code
- Intellectual property
- Regulated information
Business Impact
Consider:
- Revenue
- Operations
- Service delivery
- Reputation
- Contractual obligations
- Regulatory obligations
- Certification commitments
- Business continuity
12. Security Event Classification
The Security Event Classification Matrix should be used for consistent classification.
| Code | Classification | Description |
|---|---|---|
| CE-0 | False Positive | Activity determined to be legitimate or incorrectly detected |
| CE-1 | Routine Security Event | Genuine security-related event with no material impact |
| CE-2 | Security Weakness | Event identifies a control, configuration, or process weakness |
| CE-3 | Suspected Incident | Credible possibility of compromise but facts are incomplete |
| CE-4 | Confirmed Incident | Unauthorized activity or security incident confirmed |
| CE-5 | Major/Critical Incident | Significant security, business, customer, operational, or regulatory impact |
Classification should be based on evidence and may change as the investigation develops.
13. Severity Assessment
Where an event becomes or may become an incident, apply the organization’s Incident Severity Matrix.
Consider:
- Confidentiality impact
- Integrity impact
- Availability impact
- Customer impact
- Personal/regulated data
- Business impact
- Financial impact
- Scope
- Attacker activity
- Persistence
- System criticality
- Regulatory/contractual impact
Possible severity:
- SEV-1 — Critical
- SEV-2 — High
- SEV-3 — Medium
- SEV-4 — Low
The security event classification and incident severity are related but should remain separate decisions.
14. Escalation
Escalation should occur when the event meets defined escalation conditions.
Examples include:
- Privileged account compromise
- Cloud administrator compromise
- Active attacker
- Ransomware
- Confirmed customer-data exposure
- Personal/regulated data exposure
- Significant data exfiltration
- Production compromise
- Major production outage
- Critical supplier compromise
- Financial fraud/BEC
- Security logging manipulation
- Significant regulatory or contractual impact
Record:
| Field | Details |
|---|---|
| Escalation Required | |
| Escalated By | |
| Escalated Date/Time | |
| Escalated To | |
| Reason | |
| Severity at Escalation | |
| Incident ID | |
| Communication Reference |
15. Incident Conversion
Not every event becomes an incident.
Example
SE-2026-0045
Employee receives a phishing email.
Initial classification:
CE-1 — Routine Security Event
No credentials were entered and the email was blocked.
The event is recorded and closed.
Different Scenario
An employee clicks the phishing link and enters corporate credentials.
The event is reassessed:
CE-3 — Suspected Incident
Investigation confirms the attacker successfully authenticated.
The event becomes:
CE-4 — Confirmed Incident
A formal incident record is created:
INC-2026-0021
The event register retains the original event history and links to the incident.
16. AWS SaaS Example
Event
AWS monitoring identifies an unexpected IAM role created in the production account.
Register Entry
| Field | Entry |
|---|---|
| Event ID | SE-2026-0051 |
| Category | Cloud Security |
| Source | AWS Monitoring |
| Asset | AWS Production Account |
| Activity | Unexpected IAM Role Creation |
| Initial Classification | CE-3 |
| Initial Severity | Pending |
| Evidence | CloudTrail |
| Assigned To | Security Lead |
| Status | Investigating |
Investigation
The Security team reviews:
- CloudTrail
- IAM activity
- Role permissions
- User authentication
- MFA
- Source IP
- AWS resource activity
- S3 access
- RDS activity
- ECS activity
- Secrets access
- Security-group changes
- CI/CD activity
If the role was legitimately created through an approved change, the event may become CE-0 or CE-1.
If unauthorized creation is confirmed, it may become CE-4 and be linked to an incident.
If the compromise has significant production/customer impact, the incident severity should be reassessed using the Incident Severity Matrix.
17. Evidence Tracking
Every significant event should have an evidence reference where applicable.
| Evidence ID | Event ID | Evidence Type | Source | Date/Time | Location | Collected By |
|---|---|---|---|---|---|---|
| Log | ||||||
| Screenshot | ||||||
| Alert |
Potential evidence includes:
- Authentication logs
- Cloud logs
- Application logs
- Network logs
- EDR alerts
- SIEM alerts
- Email headers
- Screenshots
- Configuration records
- Change tickets
- Vulnerability reports
- Supplier notifications
- User reports
Evidence should be preserved according to the organization’s Evidence Preservation Procedure.
18. Corrective Action Tracking
Events classified as security weaknesses should not simply be closed without addressing the underlying issue where action is required.
| Event ID | Weakness | Action | Owner | Target Date | Status | Verification |
|---|---|---|---|---|---|---|
Examples:
Event: MFA missing for administrative account
Action: Enforce MFA
Owner: IT Lead
Verification: Authentication configuration reviewed
Event: Public cloud storage discovered
Action: Restrict public access and review exposure
Owner: Cloud Engineer
Verification: Configuration and access logs reviewed
19. Reassessment
Events should be reassessed when:
- New evidence is discovered
- Scope changes
- Unauthorized access is confirmed
- Data exposure is confirmed
- Attacker activity is identified
- Persistence is discovered
- Customer impact changes
- Business impact increases
- A vulnerability is exploited
- A supplier provides additional information
Reassessment Record
| Date | Previous Classification | New Classification | Reason | Assessor |
|---|---|---|---|---|
An event should never remain at a low classification simply because its initial assessment was low-risk.
20. Closure Criteria
An event may be closed when:
- Event has been validated
- Classification completed
- Impact assessed
- Required escalation completed
- Investigation completed, where required
- Required incident record created
- Evidence preserved
- Corrective actions assigned
- Immediate actions completed
- Residual risk considered
- Related records linked
- Closure decision documented
- Required approvals obtained
Closure Information
| Field | Details |
|---|---|
| Closure Date | |
| Closed By | |
| Final Classification | |
| Final Severity | |
| Incident ID | |
| Corrective Action ID | |
| Residual Risk | |
| Closure Rationale |
21. Security Event Dashboard
The register can be used to create management metrics.
Monthly Metrics
| Metric | Result |
|---|---|
| Total Security Events | |
| CE-0 False Positives | |
| CE-1 Routine Events | |
| CE-2 Security Weaknesses | |
| CE-3 Suspected Incidents | |
| CE-4 Confirmed Incidents | |
| CE-5 Major/Critical Incidents | |
| Events Escalated | |
| Events Converted to Incidents | |
| Open Events | |
| Closed Events | |
| Overdue Corrective Actions | |
| Average Time to Assessment | |
| Average Time to Closure | |
| Recurring Event Categories |
22. Trend Analysis
The organization should periodically analyze the register for recurring patterns.
For example:
| Trend | Possible Follow-up |
|---|---|
| Repeated phishing | Awareness / email controls |
| Repeated failed privileged logins | Identity/security review |
| Repeated cloud configuration issues | Cloud baseline improvement |
| Repeated unauthorized SaaS | Shadow IT governance |
| Repeated vulnerability events | Vulnerability management improvement |
| Repeated supplier events | Supplier risk review |
| Repeated policy violations | Training/process improvement |
| Repeated data handling errors | Data protection controls |
The purpose is not merely to count events but to identify opportunities to improve the ISMS.
23. Management Review
Security event trends can be included in management review.
Management may review:
- Number and type of events
- Significant incidents
- Recurring security weaknesses
- Major trends
- Open corrective actions
- Overdue actions
- Customer-impacting events
- Supplier-related events
- Security control failures
- Changes in risk
- Resource requirements
- Security improvement opportunities
24. Startup Implementation
A startup can implement the Security Event Register using a simple controlled spreadsheet or ticketing system.
Minimum Columns
Event ID
Date
Source
Event Title
Category
Affected Asset
Description
Information Affected
Evidence
C/I/A Impact
Customer Impact
Business Impact
Classification
Severity
Escalation
Incident ID
Action
Owner
Status
Closure Date
A dedicated GRC platform is not required simply to maintain the register.
What matters is that the organization can demonstrate a controlled process for:
Reporting → Assessment → Classification → Escalation → Response → Corrective Action → Closure
25. Relationship With Other Documents
The Security Event Register should connect to:
Security Event Reporting Form
↓
Security Event Register
↓
Information Security Event Assessment Procedure
↓
Security Event Classification Matrix
↓
Incident Severity Matrix
↓
Incident Escalation Matrix
↓
Incident Register
↓
Incident Investigation Template
↓
Incident Response Playbooks
↓
Corrective Action Tracker
↓
Incident Closure Report
↓
Lessons Learned / Management Review
This creates a traceable security-event lifecycle.
26. ISO 27001 Alignment
The register supports the organization’s processes for managing information security events and incidents, including:
- Reporting security events
- Assessing security events
- Incident management
- Evidence preservation
- Access and identity monitoring
- Logging and monitoring
- Corrective action
- Continual improvement
- Management review
The register itself is an organizational implementation tool. ISO/IEC 27001 does not prescribe this exact spreadsheet structure.
The organization should tailor the register according to its ISMS, risk assessment, Statement of Applicability, contractual obligations, and applicable legal and regulatory requirements.
27. Audit Evidence
For an audit, useful evidence includes:
- Current Security Event Register
- Sample completed event records
- Event reporting forms
- Event assessment records
- Classification decisions
- Severity assessments
- Escalation records
- Evidence references
- Related incident records
- Corrective action records
- Reclassification records
- Closure approvals
- Management review outputs
- Trend analysis
An auditor should be able to select an event and trace it from:
Detection → Reporting → Assessment → Classification → Response → Corrective Action → Closure
28. Final Audit Trail
Security Event Detected
→ Event Reported
→ Event ID Assigned
→ Event Recorded
→ Evidence Identified
→ Event Validated
→ C/I/A Impact Assessed
→ Information Impact Assessed
→ Customer/Business Impact Assessed
→ Scope Determined
→ Classification Assigned
→ Severity Assessed
→ Escalation Decision
→ Incident Created if Required
→ Investigation / Response
→ Corrective Action
→ Reassessment
→ Residual Risk Considered
→ Closure Decision
→ Management Review / Trend Analysis
Final Principle
One Event + One Unique ID + Evidence-Based Assessment + Consistent Classification + Clear Escalation + Linked Incident Record + Corrective Action + Documented Closure = Effective Security Event Management.
The Security Event Register is the bridge between everyday security alerts and formal incident management. Its value comes from preserving the complete decision trail—not simply maintaining a list of alerts.