Evidence Register

1. Purpose

The Evidence Register is the central record used to identify, track, protect, review, and retain evidence collected during information security incidents, investigations, audits, assessments, security testing, and other security-related activities.

The register provides a single traceable record showing:

What evidence was collected → Where it came from → Why it was collected → Who collected it → How it was collected → How its integrity was protected → Where it is stored → Who accessed it → What investigation or assessment it supports → How it was ultimately retained or disposed of.

The Evidence Register should work together with the Evidence Collection Procedure and Evidence Collection Form.

The register is a management and traceability record. ISO/IEC 27001 does not prescribe a specific “Evidence Register” format; organizations should maintain records appropriate to their risks, processes, contractual requirements, investigations, and audit needs.

2. Scope

The Evidence Register may be used for evidence relating to:

Security incidents
Security events
Security investigations
Account compromise
Cloud compromise
Data breaches
Phishing
Malware and ransomware
Unauthorized access
Vulnerability exploitation
Insider incidents
Supplier incidents
Production security incidents
CI/CD compromise
Security testing
Vulnerability assessments
Penetration testing
Internal audits
Compliance assessments
Risk assessments
Supplier assessments
Cloud security reviews
Access reviews
Corrective-action verification
Management investigations

3. Evidence Register Lifecycle

The evidence record should follow a controlled lifecycle:

Evidence Identified → Collection Required → Collection Authorized → Evidence Collected → Evidence Registered → Integrity Verified → Evidence Secured → Access Controlled → Reviewed → Linked to Findings → Retained/Archived → Disposed When Authorized → Closed

4. Evidence Identification

Every important evidence item should receive a unique Evidence ID.

Recommended format

EV-YYYY-0001

Example:

EV-2026-0042

Where:

EV = Evidence
2026 = Year
0042 = Sequential evidence number

The Evidence ID should remain unchanged throughout the investigation.

5. Master Evidence Register

The following table can be maintained in Excel, a GRC platform, ticketing system, or another controlled repository.

Field	Description
Evidence ID	Unique evidence identifier
Related Incident ID	Incident associated with evidence
Related Event ID	Security event associated with evidence
Investigation ID	Investigation associated with evidence
Evidence Title	Short description
Evidence Type	Log, email, configuration, screenshot, database record, etc.
Evidence Category	Identity, cloud, endpoint, network, application, database, etc.
Source System	Original system or service
Source Owner	Person/team responsible for source
Account/Tenant	Relevant account or tenant
Environment	Production, staging, development, etc.
Collection Date/Time	When evidence was collected
Evidence Time Period	Period covered by evidence
Collected By	Person who collected evidence
Collection Method	Export, API, screenshot, log download, etc.
Collection Tool	Tool/platform used
Original Location	Where evidence originally existed
Evidence Location	Secure storage location
Classification	Public/Internal/Confidential/Restricted
Sensitive Data Present	Yes/No
Personal Data Present	Yes/No
Credentials/Secrets Present	Yes/No — values must not be recorded
Integrity Required	Yes/No
Hash/Integrity Value	Hash where applicable
Hash Algorithm	SHA-256, SHA-512, etc.
Evidence Priority	Critical/High/Medium/Low
Volatile Evidence	Yes/No
Access Restricted	Yes/No
Chain of Custody Required	Yes/No
Evidence Status	Collected/Verified/Under Review/Archived/Disposed
Reviewer	Person reviewing evidence
Findings Linked	Finding/observation ID
RCA Linked	Root-cause analysis ID
Corrective Action Linked	Corrective action ID
Retention Requirement	Applicable retention period/rule
Disposal/Archive Date	Planned or actual date
Disposal Approval	Approval reference
Notes	Additional information

6. Evidence Status

Use controlled status values to prevent ambiguity.

Status	Meaning
Identified	Evidence has been identified as potentially relevant
Collection Required	Collection has been determined necessary
Authorized	Collection has been approved
Collected	Evidence has been obtained
Verified	Source, method, and integrity have been verified
Under Review	Evidence is being analyzed
Linked	Evidence has been linked to findings or conclusions
Archived	Evidence is retained but active analysis is complete
Retained	Evidence remains within the approved retention period
Disposed	Evidence has been securely disposed of
Reopened	Evidence requires additional investigation

7. Evidence Categories

A consistent category structure makes investigations and audits easier to manage.

Category	Examples
Identity	IAM logs, authentication records, SSO logs
Access	Access records, privilege changes, authorization logs
Cloud	AWS CloudTrail, GuardDuty, Security Hub
Network	Firewall, WAF, DNS, VPN, VPC Flow Logs
Endpoint	EDR, antivirus, system logs
Application	Application logs, API logs, transaction records
Database	Query logs, audit logs, database exports
Storage	S3 access logs, file activity, object history
Email	Original email, headers, attachments
Development	Git logs, CI/CD logs, deployment records
Configuration	Security groups, IAM policies, infrastructure configuration
Vulnerability	Scanner results, penetration-test evidence
Supplier	Supplier reports, security notifications, investigation records
Communication	Incident communications and approved notifications
Physical	CCTV, access-control records, physical inspection records
Documentation	Policies, procedures, approvals, meeting records
Other	Evidence not covered above

8. Evidence Priority

Evidence should be prioritized based on its potential importance to the investigation.

Priority	Description
Critical	Evidence that may be lost, changed, or materially affect investigation conclusions
High	Important evidence required to establish events, access, impact, or root cause
Medium	Supporting evidence useful for analysis or validation
Low	Contextual or supplementary information

Example

During an AWS account compromise:

Critical

CloudTrail records
IAM activity
Active sessions
Security-group changes
Evidence of data access

High

GuardDuty findings
S3 access records
Application logs

Medium

Deployment history
Related configuration records

9. Evidence Integrity

Evidence integrity should be considered based on the nature and risk of the investigation.

Where appropriate, record:

Hash value
Hash algorithm
Collection date/time
Collector
Original source
Collection method
Storage location
Evidence transfer history
Verification date
Reviewer

Example

Field	Example
Evidence ID	EV-2026-0042
File	cloudtrail-export-20260930.json
Hash Algorithm	SHA-256
Hash	Recorded in controlled evidence record
Collected By	Security Engineer
Collected	30-Sep-2026 10:35 UTC
Source	AWS CloudTrail
Storage	Restricted evidence repository
Verified By	Incident Investigator

Actual credentials, private keys, API tokens, passwords, MFA recovery codes, or secrets should never be entered into the Evidence Register.

10. Evidence Source Tracking

Each evidence item should identify its original source.

Record:

Organization
System
Application
Cloud account
Tenant
Environment
Resource
Account or identity
Source owner
Original location
Relevant time period

Example

Source

AWS Production Account
→ CloudTrail
→ ap-south-1
→ Production environment
→ IAM activity
→ 30 September 2026

This allows an investigator or auditor to understand where the evidence originated without relying on assumptions.

11. Evidence Collection Method

Record how the evidence was obtained.

Common methods include:

System export
API extraction
Security-tool export
Log download
Database query
Screenshot
Email export
File copy
Forensic acquisition
Cloud-provider export
Configuration export
Supplier-provided evidence
Physical collection
Other approved method

Where technically relevant, also record:

Tool name
Tool version
Query
Filter
Command
Export parameters
Collection procedure

12. Evidence Time Period

Evidence should clearly identify the period it covers.

Record:

Start date/time
End date/time
Time zone
Source-system time
Known clock/time synchronization issues

Example

Evidence period:
29 September 2026 00:00 UTC – 30 September 2026 12:00 UTC

Reason:
Covers the period from the first suspicious login through containment.

This prevents investigators from treating evidence outside the relevant investigation window as representative without validation.

13. Evidence Classification

Evidence should be classified according to the organization’s information classification scheme.

Example:

Classification	Typical Evidence
Public	Public security documentation
Internal	Routine system records
Confidential	Security investigation records
Restricted	Customer data, personal data, credentials-related evidence, sensitive forensic material

Evidence classification should be based on the sensitivity of the information contained within the evidence.

14. Personal and Customer Data

Evidence may contain personal, customer, financial, health, or other sensitive information.

Record whether sensitive information is present.

Question	Response
Does evidence contain personal data?	Yes/No
Does evidence contain customer data?	Yes/No
Does evidence contain regulated information?	Yes/No
Does evidence contain confidential business information?	Yes/No
Does evidence contain credentials/secrets?	Yes/No
Is access restricted?	Yes/No
Is data minimization possible?	Yes/No

Where possible:

Collect only relevant information.
Avoid unnecessary personal information.
Redact unnecessary information in working copies.
Restrict access.
Do not place secrets into investigation records.

15. Volatile Evidence

Some evidence may disappear or change quickly.

Examples:

Active network connections
Running processes
Active sessions
Temporary files
Memory
Cloud sessions
Temporary credentials
Authentication tokens
Live attacker activity

For volatile evidence, record:

Why it was considered volatile
Whether immediate collection was required
Collection time
Collection method
Whether containment was prioritized over collection

Evidence preservation should not unnecessarily delay containment where continued attacker activity presents greater risk.

16. AWS Cloud Evidence Register Example

Consider a SaaS startup that detects an unusual privileged AWS login.

Investigation

An employee reports an unfamiliar AWS administrator login.

The investigation identifies:

New IAM role
Unexpected policy modification
S3 access
Security-group modification
Unusual API activity

Evidence may be registered as follows:

Evidence ID	Evidence	Source	Purpose
EV-2026-0042	CloudTrail export	AWS CloudTrail	Establish API activity
EV-2026-0043	IAM policy history	AWS IAM	Determine privilege changes
EV-2026-0044	GuardDuty finding	AWS GuardDuty	Validate suspicious activity
EV-2026-0045	S3 access records	AWS S3	Assess data access
EV-2026-0046	Security-group history	AWS EC2	Identify unauthorized network changes
EV-2026-0047	CI/CD authentication logs	CI/CD platform	Assess possible credential reuse

All evidence should be linked to the same incident:

INC-2026-0017

The evidence should then support:

Timeline → Investigation → Impact Assessment → Root Cause Analysis → Corrective Actions → Closure

17. Evidence Access Log

Access to sensitive investigation evidence should be controlled.

Date/Time	Evidence ID	Accessed By	Purpose	Action	Approved By
30-Sep-2026 11:00	EV-2026-0042	Investigator	Timeline analysis	Viewed	Incident Commander
30-Sep-2026 11:30	EV-2026-0043	Security Lead	Privilege analysis	Downloaded working copy	Incident Commander

The access log is particularly important for restricted evidence.

18. Evidence Transfer

Where evidence is transferred between people, systems, suppliers, legal counsel, investigators, or service providers, record:

Evidence ID
Sender
Recipient
Date/time
Transfer method
Purpose
Integrity verification
Authorization
Destination
Chain-of-custody reference

Only approved secure transfer methods should be used.

19. Evidence Review

The investigator or reviewer should determine whether the evidence is:

Relevant
Complete
Reliable enough for the intended purpose
Consistent with other evidence
Within the correct time period
From an identifiable source
Properly protected
Sufficient to support the conclusion

Evidence should not automatically be treated as proof simply because it exists.

Investigators should distinguish between:

Evidence → Observation → Interpretation → Hypothesis → Finding → Conclusion

20. Evidence Gaps

The register should also record missing or unavailable evidence.

Evidence Gap	Reason	Impact	Alternative Evidence	Risk
Missing authentication logs	Logging not enabled	Cannot confirm login source	SSO logs	Medium
Missing application logs	Retention expired	Limited transaction analysis	Database audit logs	High

An evidence gap should not simply be marked “N/A.”

The organization should understand whether the missing evidence affects the investigation conclusion.

21. Evidence Relationships

Evidence should be linked to related ISMS records wherever practical.

Example:

EV-2026-0042

↓

INC-2026-0017 — Cloud Account Compromise

↓

INV-2026-0017 — Investigation

↓

RCA-2026-0017 — Root Cause Analysis

↓

CA-2026-0038 — Corrective Action

↓

LR-2026-0012 — Lessons Learned

↓

IR-2026-0008 — ISMS Improvement

This creates a traceable evidence chain across the ISMS.

22. Evidence Retention

Retention should be determined based on applicable:

Legal requirements
Regulatory requirements
Contractual requirements
Customer commitments
Insurance requirements
Investigation requirements
Litigation requirements
Internal security requirements
Organizational retention policy

The Evidence Register should record the applicable retention requirement rather than relying on informal decisions.

23. Evidence Disposal

Evidence should only be disposed of when:

The retention requirement has expired.
No investigation requires continued retention.
No legal hold applies.
No contractual requirement requires retention.
Disposal is authorized.
Disposal is performed securely.
Disposal is recorded.

Example:

Evidence ID	Retention End	Approval	Disposal Date	Method	Status
EV-2026-0018	30-Sep-2028	Security Lead	01-Oct-2028	Secure deletion	Disposed

24. Evidence Register Review

The register should be reviewed periodically during an investigation.

Review questions:

Has all required evidence been identified?
Has critical evidence been collected?
Are evidence sources documented?
Are collection methods recorded?
Has integrity been verified where required?
Is access appropriately restricted?
Are evidence gaps documented?
Are findings linked to evidence?
Are important conclusions supported?
Are retention requirements defined?
Are disposal decisions authorized?

25. Evidence Register Quality Checks

Before closing an investigation, verify:

☐ Every evidence item has a unique Evidence ID
☐ Related incident/investigation IDs are recorded
☐ Source is identified
☐ Collection date/time is recorded
☐ Evidence time period is recorded
☐ Collection method is documented
☐ Collector is identified
☐ Classification is assigned
☐ Sensitive information has been identified
☐ Integrity requirements have been assessed
☐ Hash recorded where required
☐ Storage location is documented
☐ Access restrictions are applied
☐ Chain of custody is maintained where required
☐ Evidence gaps are documented
☐ Findings are linked to evidence
☐ Retention requirement is defined
☐ Disposal/archival requirements are defined
☐ Reviewer has completed the review

26. Startup-Friendly Implementation

A startup does not need an expensive forensic platform just to maintain evidence traceability.

A practical model can start with:

Security Alert/Event → Incident ID → Evidence ID → Secure Evidence Repository → Evidence Register → Investigation → Findings → RCA → Corrective Action → Closure

Minimum spreadsheet columns

Evidence ID	Incident ID	Evidence Title	Source	Collection Date	Collector	Method	Classification	Storage	Integrity	Finding Linked	Status

For an AWS SaaS startup, evidence may initially come from:

AWS CloudTrail
AWS GuardDuty
AWS Security Hub
IAM
S3
VPC Flow Logs
WAF
Application logs
Database audit logs
CI/CD logs
SSO/identity provider
Endpoint security tools
Email systems

The objective is traceability and integrity, not documentation volume.

27. Relationship With Other Evidence Documents

Document	Purpose
Evidence Collection Procedure	Defines how evidence should be collected
Evidence Collection Form	Records details of an individual collection
Evidence Register	Centrally tracks all evidence
Chain of Custody Form	Records formal evidence transfers
Incident Timeline	Establishes what happened and when
Incident Investigation Template	Performs the investigation
Root Cause Analysis	Determines why the issue occurred
Corrective Action Tracker	Tracks actions resulting from findings
Incident Closure Report	Documents final incident outcome

The relationship can be summarized as:

Procedure = How

Collection Form = What Was Collected

Evidence Register = What Evidence Exists

Chain of Custody = Who Handled It

Investigation = What It Shows

RCA = Why It Happened

Corrective Action = What Will Change

Closure Report = What Was Ultimately Decided

28. ISO 27001 Alignment

The Evidence Register can support the organization’s implementation of ISO/IEC 27001 by providing controlled information relating to areas such as:

Information security incident management
Event reporting and assessment
Evidence preservation
Access control
Logging and monitoring
Information classification
Records and documented information
Supplier/security investigations
Risk treatment
Corrective actions
Continual improvement

The exact evidence-management process should be determined according to the organization’s risk, operational requirements, legal obligations, and ISMS scope.

The Evidence Register should also be considered alongside the organization’s risk assessment, risk treatment plan, Statement of Applicability, incident management process, and applicable Annex A controls.

29. Audit Evidence

During an internal or external audit, the Evidence Register can demonstrate:

Evidence was systematically identified.
Evidence sources were known.
Evidence collection was controlled.
Sensitive evidence was protected.
Evidence integrity was considered.
Access was restricted.
Evidence was linked to investigations and findings.
Evidence gaps were identified.
Retention was defined.
Disposal was controlled.

An auditor should be able to select an Evidence ID and trace it back to its source and forward to the resulting investigation finding or corrective action.

30. Final Audit Trail

A complete evidence-management trail should look like:

Evidence Requirement Identified

→ Evidence Source Identified

→ Collection Requirement Defined

→ Collection Authorized

→ Evidence Collected

→ Evidence ID Assigned

→ Source Recorded

→ Collection Method Recorded

→ Time Period Recorded

→ Integrity Verified

→ Classification Assigned

→ Evidence Secured

→ Access Restricted

→ Evidence Reviewed

→ Finding Linked

→ Evidence Gap Recorded Where Applicable

→ Investigation/RCA Supported

→ Corrective Action Linked

→ Retention Determined

→ Evidence Archived or Disposed

→ Disposition Recorded

→ Evidence Record Closed

31. Final Principle

Every important piece of evidence should have an identity, a source, a collector, a time, a collection method, an integrity record where appropriate, a secure location, controlled access, and a traceable relationship to the investigation or assessment it supports.