What You Don’t Know WILL Hurt You – The Hidden Risk of Shadow APIs

In our last newsletter, we discussed the T-Mobile API breach and the critical importance of securing APIs. Today, we’re tackling a less obvious but equally dangerous risk—Shadow APIs.

These hidden threats can quietly expose your business to breaches, compliance violations, and reputational damage. Let’s break down what shadow APIs are, why they’re dangerous, and how you can protect your organisation.

What Are Shadow APIs?

Shadow APIs are undocumented, unmonitored, or forgotten APIs that exist in your environment without your knowledge. They often emerge in three common scenarios:

1. Developer Oversight: APIs created for testing or internal use that are never decommissioned.

2. Third-Party Integrations: APIs introduced by vendors or partners that aren’t properly tracked.

3. Legacy Systems: Outdated APIs left behind by old systems that are no longer maintained but still accessible.

Because they fly under the radar, shadow APIs are invisible to your security team, making them a prime target for attackers.

The Risks of Shadow APIs

Shadow APIs pose significant risks to your business, including:

1. Lack of Visibility and Protection

Since shadow APIs aren’t documented, they’re excluded from security policies, monitoring, and testing. This makes them an easy entry point for attackers to exploit.

2. Outdated and Vulnerable Code

Many shadow APIs run on deprecated versions with known vulnerabilities. Without updates or patches, they’re a low-hanging fruit for exploitation.

3. Compliance Violations

Shadow APIs can expose sensitive data, leading to breaches of regulations like GDPR, NDPR or CCPA. This could lead to hefty fines and a damaged reputation.

How to Identify and Eliminate Shadow APIs

To protect your business, you need a proactive approach to uncover and address shadow APIs. Here’s a step-by-step plan:

1. Conduct a Comprehensive API Inventory

Use API discovery tools to scan your environment and identify all APIs—documented and undocumented. Catalog each API, its purpose, and its security status.

2. Monitor API Traffic Continuously

Implement real-time monitoring to detect unusual activity or unauthorized access attempts. Pay special attention to APIs that are receiving traffic but aren’t documented.

3. Scan Code Repositories Regularly

Use automated tools to scan your codebase for undocumented API references or calls. This helps uncover hidden APIs that developers may have created without proper documentation.

4. Conduct API Penetration Testing

Regularly test your APIs—both known and newly discovered—to identify and fix vulnerabilities before attackers can exploit them. APISec has a fully automated tool that can help with this. Penetration testing is a proactive way to validate your API security posture.

5. Enforce Strong API Governance

Establish clear policies for API creation, documentation, and decommissioning. Ensure every API undergoes a security review before deployment.

6. Educate Your Team

Train developers and engineers on the risks of shadow APIs and the importance of proper API management. Foster a culture of accountability and transparency.

The Business Impact of Ignoring Shadow APIs

Ignoring shadow APIs is a business risk that comes with serious consequences. A single unsecured shadow API can lead to:

• Data breaches exposing sensitive information

• Regulatory fines for non-compliance

• Reputational damage that erodes customer trust

• Financial losses from downtime and recovery efforts

The bottom line? Shadow APIs are a weak link in your security chain that you can’t afford to overlook.

Take Action Today

Need help securing your APIs? I’m here to help—let’s talk about creating a strategy to safeguard your business and your customers.

👉 Book a free consultation here
👉 Follow me on LinkedIn to stay up-to-date with the latest in API security.

In our next newsletter, we’re tackling a huge challenge:
How do you get leadership to care about API security—and make it a core part of the business strategy?

Because if security and strategy aren’t working together, everyone loses.

🔥 Stay tuned—you won’t want to miss this one.

Talk soon,
Damilola