Shadow APIs are undocumented, unsupervised, or hidden API endpoints in an organization's infrastructure. Sometimes, they do not actively manage or protect the APIs, so these shadow APIs occur due to old systems, development sprawl, third-party integrations, and internal experiments. Shadow APIs are not subject to security standards or governance frameworks, making them vulnerable to security threats, data breaches, and compliance difficulties.

This blog will explore shadow APIs, their associated risks, and remediation measures for them. Check out the comparison between shadow and zombie APIs and detection and prevention measures for shadow APIs.

What is a Shadow API?

Shadow API is an undocumented and unmanaged API within the organization. Developers often unintentionally create them during application development or while executing other business operations.

Shadow APIs pose serious risks to an organization’s digital transformation because they leak important data and cause unauthorized access. Identifying, managing, and protecting these APIs are important for allowing complete API security and compliance.

Risks of Shadow APIs

Shadow APIs can leak sensitive data and create entry points for attacks. Here are some of the risks associated with shadow APIs:

Security Risks

Shadow APIs increase the attack surface by exposing undocumented endpoints that lack security controls. Due to their weak authentication and poor encryption, APIs become easy targets for attackers.

Attackers can exploit them to get unauthorized access, manipulate data, or perform injection attacks (like SQL and XML). The mismanagement of shadow APIs can lead to data breaches, operational disruptions, and account takeovers.

Compliance and Regulatory Risks

Shadow APIs can result in non-compliance with GDPR, HIPAA, PCI-DSS, and CCPA, leading to legal and financial penalties. These APIs may process sensitive data without proper encryption, access controls, or permission mechanisms. Inaccurate API inventories can also lead to failed audits and reputational damage.

Operational Risks

Shadow APIs can cause inefficiencies, system failures, and higher maintenance costs. Shadow APIs operate outside the API governance, so they may cause service disruptions and integration issues. As shadow APIs are not part of the API management framework, it can lead to connection issues in existing systems, reduce performance, or cause upgrade failures.

Data Exposure and Leakage

Shadow APIs can unintentionally expose a sensitive data because of insufficient security controls, misconfigurations, or excessive data exposure. If they are not encrypted, attackers can access data during transmission, resulting in breaches of personally identifiable information (PII) and financial records. APIs that are not secure may also allow attackers to manipulate private business information, causing compliance violations.

Business Risks

Shadow APIs can lead to financial losses, reputational damage, and operational inefficiencies. The Data breaches may result in legal penalties, customer distrust, and a loss of commercial possibilities. Duplicate or unmanaged APIs will increase development and maintenance costs and cause integration issues.

Shadow APIs vs Zombie APIs

Shadow and Zombie APIs pose significant operational and security risks, though their impact and nature differ. Here are some of the key differences between shadow and zombie APIs:

Preventing Shadow APIs

Proactively detecting and managing shadow APIs is crucial for data protection. The following preventive measures can help organizations maintain robust security:

API Discovery and Inventory Management

One of the most effective methods to avoid Shadow APIs is to keep an up-to-date API inventory. Use API discovery tools to check networks and find a unmanaged APIs that may be operating without supervision. Security teams can monitor all APIs, including internal, external, and third-party APIs, by creating a single API inventory, which ensures that undocumented APIs are not vulnerable.

Implement API Governance

Effective API governance is important for removing shadow APIs and reducing security threats. Organizations must follow strict rules to ensure they register, document, and review all APIs before installation. Implementing access controls, authentication systems, and continuous monitoring can prevent unwanted API usage.

Monitor API Traffic

Organizations require continuous API monitoring to detect suspicious activity. Use API security tools to analyze API traffic in real-time and detect irregularities. Set automated alerts to receive notifications about unauthorized API requests, excessive data exposure, and irregular traffic patterns. Regularly monitoring API activity helps identify malicious or misconfigured APIs that may leak personal data.

Secure API Lifecycle Management

Proper API lifecycle management is essential to reduce the risk of Shadow APIs. Use version control to track all changes and remove outdated APIs. Regularly conduct security audits to ensure that security standards are met and that all APIs follow the company's guidelines.

Remediation Measures for Shadow API Attacks

It's essential to take action to check the damage and take preventative measures during a shadow API attack. Here are some of the remediation measures for shadow API attacks:

Identify and Limit the Attack

Security teams can use discovery tools, network analysis, and security logs to detect the affected endpoints and remove the shadow APIs quickly. If the security team identifies an unauthorized API, quick control measures, such as blocking access and removing affected systems, can prevent it from spreading to other connected systems.

Check Data Exposure

Analyze API access logs to identify unauthorized users, exposed data, and any possible changes. If private data, such as personally identifiable information (PII) or financial records, is disclosed, notify stakeholders and follow data breach response protocols.

Strengthen Security Controls

After evaluating the impact, handle the underlying cause of the attack. If the Shadow APIs are vulnerable because of poor authentication, missing encryption, or improper access controls, execute changes immediately. This includes authentication protocols such as OAuth 2.0, enabling API rate restriction, mandating TLS encryption, and establishing strong access controls.

Conduct API Audits

To prevent future attacks, check all APIs to find any additional undocumented or vulnerable APIs in their infrastructure. This includes doing regular API discovery scans, assessing third-party integrations, and monitoring cloud environments for unmanaged APIs. Use a strong API inventory management system to detect all APIs and ensure they follow security policies.

Final Thoughts

Shadow APIs pose serious threats to security, compliance, and operational efficiency. If organizations do not check or manage them efficiently, they can expose data, cause security breaches, interrupt services, and violate regulations. To reduce these risks, use a proactive approach that combines API discovery, continuous monitoring, governance enforcement, and security testing.

Akto is an advanced API security platform that helps organizations find, test, and protect APIs. With automated discovery, continuous security testing, and real-time threat detection, Akto ensures that APIs are secure and compliant. Schedule a demo with Akto to provide excellent API security and find hidden APIs.