Module 8: Logging, Audit Trails, and Incident Reporting
"You cannot secure what you cannot trace."
Module Objective
This module trains your engineering, treasury, support, compliance, and fraud ops teams to:
Establish tamper-proof audit trails across virtual card systems
Build logs that help explain and reconstruct incidents
Enable reporting that satisfies internal, partner, and scheme-level requirements
Make fraud investigations fast, reliable, and reproducible
The Importance of Logging in Virtual Card Systems
Virtual cards are ephemeral — they're created, funded, used, frozen, or terminated in minutes. If you don't log each state, you'll never know what went wrong when fraud or operational failure occurs.
Logging is also the primary input for security, compliance, and dispute resolution.
What Should Be Logged?
1. Card Lifecycle Logs
| Action | What to Log |
|---|---|
| Creation | cardId, userId, IP, deviceHash, BIN, time |
| Freeze/Unfreeze | cardId, reason, actor, time |
| Termination | cardId, terminationType (manual, auto), trigger, time |
| Top-up | amount, walletId, float source, topUpRef, time |
| Withdrawal | amount, float destination, userId, status, time |
2. Transaction Logs
| Action | What to Log |
|---|---|
| Authorization | cardId, amount, MCC, merchantName, BIN, country, success/fail |
| Refund | cardId, refundRef, originalSpendRef, amount, sourceMCC, status |
| Reversal | cardId, reversalRef, merchantName, originalAuthId |
| Chargeback | cardId, chargebackRef, merchant, reason, status, fee |
| Decline | reason, declineCode, retry attempts |
3. Security Events
| Action | What to Log |
|---|---|
| Login | userId, IP, deviceHash, 2FA method |
| API key usage | IP, action, endpoint, auth status |
| Webhook activity | delivery status, headers, payload hash, retries |
| Failed webhook signature | cardId, endpoint, timestamp, source |
Audit Trails
An audit trail is a time-sequenced, immutable history of all actions taken on or by a system. It's not just logs — it's structured accountability.
Every audit trail entry should include:
timestamp
actor (user, API key, system job)
action (e.g., freeze card, authorize spend)
target (cardId, userId, walletId)
before/after state
origin (IP, device, internal service)
correlationId (for grouping related actions across services)
These trails help in:
Regulatory investigations
Merchant disputes
Support complaint resolution
Chargeback defense
Internal compliance reviews
Fraud & Risk Reporting Templates
Every confirmed fraud incident must be documented in a reproducible and shareable format. Create reports that support:
Scheme audits
Treasury float reconciliation
Engineering post-mortems
Legal escalation
Team training
Incident Report Template (Fraud)
| Field | Description |
|---|---|
| Case ID | Unique identifier, e.g. FRC-2024-0012 |
| User ID(s) | All associated users |
| Card ID(s) | All cards involved |
| Merchant(s) | Names, MCCs, processor info |
| Float Impact | Value affected |
| Action Timeline | Full chain of actions by timestamp |
| Containment Steps | Freezes, locks, fund moves |
| Decision Log | What was done, by whom, why |
| Lessons | What to change next |
| Attachments | Logs, screenshots, charts |
Tooling Recommendations
| Purpose | Tool/Process |
|---|---|
| Central logging | Elastic, Datadog, or self-hosted Loki + Grafana |
| Log retention | At least 1 year for all card and transaction logs |
| Alerting | Real-time alerts for flagged MCCs, reversals, chargebacks |
| Risk dashboard | Internal UI that visualizes card lifecycle and actions |
| Export tooling | Ability to export fraud reports for regulators and partners |
Developer Practices
Developers must:
Log every mutating action on a card or user account
Add correlationId to every system-initiated card operation
Validate and enforce webhook signature checks
Avoid overwriting logs with retries or updates — append only
Provide APIs to query logs per user/card/ref for support teams
What Not to Miss
Log decline codes with explanations
Keep a reason field for every freeze, unfreeze, or termination
Use consistent reference IDs across systems for reconciliation
Enable log search by time, user, cardId, and merchant
Don't log PII or CVV values in plaintext
Module 8 Knowledge Check
1. What should be logged when a card is frozen?
A. Only the time
B. Only the cardId
C. cardId, reason, actor, and timestamp
D. Just the freeze status
Answer: C
2. Why are audit trails critical?
A. They reduce payment fees
B. They track marketing spend
C. They enable accountability and traceable decisions
D. They automate refunds
Answer: C
3. What is a correlation ID useful for?
A. Tracking device geolocation
B. Matching merchant records
C. Connecting related actions across systems
D. Mapping MCC categories
Answer: C
