Mustafa ERBAY

Posted on Aug 9 • Originally published at mustafaerbay.com.tr

The First 30 Minutes When an API Key Leaks: A Rotation Runbook

#api #guide #software

A leaked API key poses a serious threat to system security and requires rapid intervention. This situation can lead to undesirable consequences such as unauthorized access, data breaches, or service interruptions. When an API key leak is detected, the steps taken within the first 30 minutes are vital for minimizing potential damage and ensuring the system returns to normal operation. This runbook provides a practical, step-by-step response plan against a leaked API key.

This emergency runbook outlines the steps you should follow when an API key leak is suspected. The goal is to limit damage, find the source of the leak, and restore systems to a secure state. Acting quickly and in a coordinated manner is the most important factor in such security incidents.

How to Detect an API Key Leak?

API key leaks typically manifest through unexpected system behaviors or notifications from external sources. Early detection shortens the response time, reducing potential damage. Therefore, establishing proactive monitoring and anomaly detection mechanisms is critical.

When working in a production environment, you might encounter symptoms such as unexpected traffic surges, failed authorization attempts, or requests from suspicious IP addresses. Especially in critical systems like a production ERP, unexpected data read or write operations associated with a specific API key should raise the alarm level. Regularly reviewing logs is the most fundamental way to spot such anomalies.

Common Detection Methods

Various methods and tools are available for detecting API key leaks. Using these methods in combination helps identify leaks more quickly and reliably.

Log Monitoring and Anomaly Detection: Regularly monitor logs from your API gateways or application servers. High-volume requests from unexpected IP addresses, unusual API calls (e.g., calls to endpoints not normally used), or failed authentication attempts can be signs of a leak. Automated anomaly detection systems (e.g., SIEM tools) are highly beneficial in this process.
Security Tools and Services: Code hosting platforms like GitHub have secret scanning features that automatically scan your repositories for sensitive information like API keys. Such services alert you if a key is accidentally committed to a code repository. Similarly, some cloud providers (e.g., AWS Secrets Manager, Azure Key Vault, Google Secret Manager) or third-party security firms offer external scanning services that check for leaked sensitive information.
User and System Notifications: Sometimes, leaks can also surface through user feedback from your application, such as "application not working" or "unexpected behavior." Additionally, third-party service providers (e.g., payment gateways, SMS services) using the API key might alert you due to anomalies in their own systems. It's crucial to take such notifications seriously and investigate immediately.

💡 For Proactive Monitoring

Establish expected patterns of your API calls (rate, source IP, call types) as a baseline. Deviations from this baseline should trigger an anomaly detection system. For example, an endpoint that normally receives 1000 calls a day suddenly receiving 10,000 calls should be investigated.

First 5 Minutes: Leak Verification and Communication

When an API key leak is suspected, the steps taken within the first 5 minutes are critical for determining the scale and impact of the incident. Instead of panicking, it's necessary to calmly follow established procedures. At this stage, verifying whether the key has actually leaked and informing the relevant teams are priorities.

Verifying a Suspected Leak

Quickly follow these steps to verify a suspected leak:

Attempt Access to the Relevant API: Try to access the relevant API using the suspected leaked API key (or by examining request logs from a suspicious source). If the key is still active and unauthorized access is possible, the leak is confirmed. Be sure to perform this attempt in your own controlled environment.
Review Log Records: Search API gateway, load balancer, or application server logs for abnormal or unauthorized requests made using the suspected leaked key. Check source IP addresses, request times, and called endpoints. This review provides initial information about the scope of the leak.

Emergency Communication Plan

Immediately after the leak is confirmed, activate a predefined communication plan. Transparent and rapid communication is vital for managing the incident.

Inform Relevant Teams: Immediately notify key stakeholders such as the Incident Response team, security team, DevOps team, and senior management. Use appropriate communication channels (emergency announcement, a dedicated chat channel) depending on the severity of the incident.
Communication Content: The initial notification should include a brief summary of the incident, the identified key, and the potential impact. Detailed analyses and resolution steps will be shared in later stages. Your goal is to keep everyone informed and ensure coordination.

Emergency Response: Key Revocation and Access Blocking

The moment a leaked API key is verified, the highest priority step is to immediately terminate its authorization. Revoking the key instantly stops unauthorized access and prevents potential malicious actions. The faster this step is taken, the better your systems and data will be protected.

The revocation process can be done through your API provider's management console, API, or CLI (Command Line Interface). For example, to revoke a cloud provider's API key, you might need to use a specific console interface or a command-line tool like aws cli. This process can vary depending on your service, so it's important to review the relevant documentation beforehand.

Revoking the Leaked Key

Revoke the Key: Go to the platform where the API key was created (e.g., AWS IAM, Google Cloud Console, Stripe Dashboard, your own API management panel). Locate the leaked key and immediately revoke or delete it. On many platforms, this action can be performed with a single click or command. To delete an IAM user's access key using the AWS CLI, the following command can be used:
```
# Example: Command to delete an IAM user's access key via AWS CLI
aws iam delete-access-key --access-key-id AKIAIOSFODNN7EXAMPLE --user-name Alice
```
The output of this command usually indicates success if it doesn't contain any error messages. However, additional verification steps should be taken to ensure the key is truly disabled.
Evaluate Post-Revocation Effects: Revoking the key will also stop legitimate applications or services that use it. This may lead to a brief service interruption. Therefore, it's important to identify affected applications and services and make necessary announcements before or simultaneously with the revocation. Rapid deployment of a new key should be planned to minimize disruption.
Verify Revocation: To ensure the key has truly been disabled, try making an API call using the leaked key. This call should return an authorization error (e.g., HTTP 401 Unauthorized). This verification confirms the operation's success.

Access Blocking and Restrictions

While key revocation is often sufficient, you might also consider access blocking measures as an additional layer of security.

IP-Based Blocking: If you have identified suspicious IP addresses used with the leaked key, block all traffic from these IP addresses on your firewalls or WAF (Web Application Firewall). This can be effective, especially if you suspect the leak's source is a specific attacker.
Rate Limiting and DDoS Protection: Implement stricter rate limiting rules on your API gateways or load balancers to catch and block unusual traffic patterns. This helps prevent potential DDoS attacks or brute-force attempts.

⚠️ Caution: Incorrect Key Revocation

Revoking the wrong key can cause critical systems to shut down. Before revoking, double-check the key's ID and the service it's associated with. Remember that you need to log in as the root user to delete AWS root user access keys. This risk is lower in automated systems, but caution is essential in manual interventions.

Damage Assessment and Scope Analysis

After the API key is revoked and the immediate threat is contained, a detailed damage assessment and scope analysis are crucial to understand the true extent of the incident and the harm it caused. This phase is fundamental for determining the impact of the leak, understanding if a data breach occurred, and laying the groundwork for preventing similar future incidents. This analysis is not just about immediate response but also a part of long-term security strategies.

Scope of the Leaked Key's Permissions

Focusing on the permissions held by the leaked key is the first step in understanding potential damage.

Permission Level Analysis: Determine which resources (databases, storage services, other APIs) and for which operations (read, write, delete) the key had authorization. Keys designed with the Principle of Least Privilege will have a more limited impact in the event of a leak.
Identify Affected Resources: List all systems, data stores, and services that the key could access. This provides a comprehensive picture of all potentially affected assets.

Log Analysis and Anomaly Detection

Thoroughly reviewing logs from the time the leaked key was active can reveal which data was accessed or manipulated.

Create a Timeline: Precisely determine the time frame between when the leak began and when the key was revoked. Filter all API calls made using the leaked key within this time frame.
Examine Suspicious Requests:
- Source IP Addresses: Check the geographical locations of the IP addresses from which requests originated and look for deviations from normal usage patterns. Requests from unknown or suspicious sources should raise an alarm.
- Called Endpoints: Check if the key was used to call endpoints not normally accessed or those that access sensitive data.
- Data Read/Write Operations: If the key had write permissions, investigate whether any data manipulation or deletion occurred. Database logs and application logs are highly valuable at this stage.
```
# Example: Searching for API key usage in logs of a specific service with journalctl
journalctl -u my-api-service | grep "API_KEY_ID_OF_LEAKED_KEY" | less
```
The journalctl command is used to query and display log entries stored by systemd-journald. The -u flag is used to filter logs for a specific unit (service).

Potential Data Breach Assessment

Evaluate whether a data breach occurred using the collected log data.

Sensitive Data Access: Determine if the leaked key accessed sensitive data such as customer information, financial data, or personally identifiable information (PII).
Evidence Collection: Gather all relevant logs, configurations, and analysis results to create a complete picture of the incident. This information may be necessary for a forensic analysis or legal proceedings.

New Key Creation and Distribution Strategies

After the leaked API key is revoked and damage assessment is complete, a new key must be created and securely distributed for systems to return to normal operation. This process not only ensures business continuity but also involves adopting best practices to minimize future leak risks. Secure key creation and avoiding anti-patterns like hardcoding are essential.

Securely Creating a New API Key

When creating a new API key, it's important to adhere strictly to security principles.

Principle of Least Privilege: Grant the new key only the minimum permissions it needs. For example, do not define write or delete permissions for a service that only requires data read access. This limits the impact of a potential future leak.
Strong Key Generation: Use your API provider's automated key generation mechanisms. Avoid manual key creation and ensure that keys are sufficiently long, complex, and unpredictable.
Short-Lived Credentials: If possible, prefer using keys that automatically expire after a short period. This reduces the risk of a key remaining active for a long time and potentially being misused.

Secure Key Distribution Methods

Securely delivering the new key to your applications and services is fundamental to reducing the risk of leaks.

Secret Management Systems: Utilize dedicated secret management systems such as HashiCorp Vault, AWS Secrets Manager, Azure Key Vault, or Google Secret Manager. These systems store keys in an encrypted manner and provide access only when authorized applications or services need them.
CI/CD Pipeline Integration: Integrate the distribution of the new key into your CI/CD (Continuous Integration/Continuous Delivery) pipelines. This reduces manual intervention, prevents human error, and ensures the key is updated securely. Your pipeline should retrieve the new key from the secret management system and inject it into the relevant services.
```
# Example: Secret usage in a CI/CD pipeline (a general template)
deploy:
  stage: deploy
  script:
    - SECRET_VALUE=$(vault read -field=value secret/my-api-key) # Read secret from Vault
    - kubectl set env deployment/my-app API_KEY=$SECRET_VALUE # Inject secret into Kubernetes
  only:
    - main
```
Avoid Hardcoding: Absolutely do not hardcode API keys directly into code, configuration files (especially those committed to version control systems), or environment variables. This is one of the most common causes of leaks. Always use secure secret management mechanisms.

ℹ️ Deployment Strategies and Continuity

Using strategies like blue/green or canary deployment for new key distribution can help minimize service disruption. First, deploy the new key to a small group of users, and if there are no issues, direct all traffic to the new version.

Long-Term Measures and Automation

After an incident like an API key leak, merely responding in the moment is not enough. Taking long-term measures and automating processes is vital to prevent similar incidents in the future and strengthen the overall security posture. This is part of building a culture of continuous improvement and security awareness.

Finding and Addressing the Root Cause of the Leak

To prevent a leak from recurring, it's necessary to understand its root cause and eliminate it.

Post-Mortem Review: Conduct a detailed post-mortem analysis covering all aspects of the incident. Determine how the leak occurred and which processes or controls failed. This may include technical, procedural, or human factor deficiencies.
Remediate Vulnerabilities: Take corrective actions for the identified root causes. This might involve strengthening code review processes, tightening access controls, increasing developer training, or integrating automated security tools. For example, if the key leaked because a developer accidentally committed it to a public repo, adding pre-commit hooks or secret scanning steps to the CI/CD pipeline could be a solution.

API Key Management Policies and Automation

Proactive API key management is key to preventing future leaks.

Regular Rotation: Ensure all API keys are automatically rotated within a specific timeframe (e.g., every 90 days). This reduces the risk of a key remaining leaked for an extended period. Automated rotation can be done with secret management systems or custom scripts.
Short-Lived Keys and JIT (Just-in-Time) Access: Whenever possible, use short-lived API keys or temporary credentials that are valid only for a specific task or time interval. JIT access models ensure that keys are active only when needed.
Multi-Factor Authentication (MFA) and Least Privilege: Enforce MFA for users and systems that access API keys. Also, ensure that each key has only the minimum privileges required to perform a specific task.
Automated Secret Scanning: Continuously use automated tools to scan your code repositories, CI/CD pipelines, and even production environment configurations for sensitive information (API keys, passwords). These tools can quickly detect and notify about accidentally leaked keys.

Continuous Training and Awareness

The human factor plays a significant role in security, as do technological measures.

Developer Training: Provide your developers with regular training on secure coding practices, secret management best practices, and the importance of API key security.
Security Awareness: Ensure all employees are knowledgeable about security policies and procedures. Raise awareness about risks such as social engineering attacks and phishing.

Conclusion

An API key leak is a critical security incident that must be addressed quickly. By following the steps outlined in this runbook, it's possible to minimize the impact of the leak and restore your systems to a secure state. Rapid and coordinated intervention within the first 30 minutes is vital for limiting potential damage.

However, it's important to remember that proactive and continuous security measures are just as crucial as immediate response for preventing future leaks. Regular key rotation, secure secret management systems, CI/CD integration, and continuous developer training are the cornerstones of a robust API security posture. Implementing these steps not only resolves an incident but also strengthens your overall security culture.

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