This cyber exercise addresses the vulnerability of software supply chain compromise, which in this case leads to the exfiltration of sensitive user information. The aim is to emphasize the key points for preventing and mitigating this type of attack vector.

2. Library Compromise

Attack Description

• Attacker introduces a backdoor into the library.

• Uploads the malicious version to the public repository (GitHub, PyPI, npm, etc.).

• A seemingly valid digital signature goes undetected.

Reflection

What review controls do you have for external dependencies (SCA, signing, change tracking)?

How do you monitor new versions in public repositories for critical libraries?

Is there an official communication channel with open-source vendors for security alerts?

3. Deployment in Test and Production Environments

Deployment Chain

• CI/CD pipeline that automatically obtains the latest version.

• Deployment to a test environment without additional validation.

• Promotion to production based on a green/blue gateway or direct push.

Reflection

Do you have manual or automatic checkpoints before promoting a new dependency?

What security tests (SAST, DAST) are applied to builds that include external libraries?

How would you separate test and production environments to prevent cross-contamination?

4. Card Information Exfiltration

Exfiltration Techniques

• Data capture in the tokenization function.

• Encrypted batch transmission to a server controlled by the attacker during test transactions.

• Use of hidden SMTP/HTTPS channels in debug logs.

Reflection

How would you detect unusual data exfiltration (IDS/IPS, WAF, EDR)?

Which logs would you review to identify suspicious traffic?
Do you have alerts configured for atypical volumes of outgoing data?

5. Alteration of Payment Functionality

Impact on the Payment Process

• Diversion of transactions to the attacker's accounts.

• Introduction of errors (timeouts, 500 errors) at critical moments.

• Unauthorized modification of amounts or discounts.

Reflection

How would you validate the integrity of transactions in the face of anomalies?

What rollback or circuit breaker mechanisms exist in the payment pipeline?

Who receives the alert if the payment gateway generates recurring errors?

6. Protection Measures

Prevention Against Supply-Chain Attacks

• Registration and blocking of unauthorized versions (version allowlist).

• Continuous dependency scanning (SCA).

• Change reviews and artifact signing.

Recognition of System Anomalies

• Service health monitoring (ping, latency, error rates).

• Binary integrity alerts (tripwire, checksums).
• Audit of deployment logs and Canary Islands deployment.

Reflection

Do you know which critical dependencies you use and their version cycle?
Do you have a tool that detects changes in production artifacts (hash drift)?
Which teams are authorized to approve production deployments?

7. Backups and Recovery

Backup Strategy

Segment sensitive data (cards, payment history) and encrypt it at rest.
Replicate backups outside the main network (air-gapped).
Periodic restoration tests (DR drills).

Reflection

How long would it take to restore the payments database to a state prior to the incident?
Are there sandbox environments to validate backups before going to production?
How do you guarantee transactional consistency after a restore?

8. Measures to Prevent and Mitigate

Best Practices Checklist

Maintain an up-to-date inventory of all libraries and versions used.

Implement branch protection and strict repository review rules.
Automatically scan for SCA vulnerabilities on every push/merge.
Validate artifact signatures with internal PKI.
Monitor library usage patterns (critical functions) in real time.
Provide specific incident response playbooks for supply-chain attacks.
Conduct tabletop exercises and recovery simulations for this scenario.