API Security: Why Application Programming Interfaces Are a Major DevOps Vulnerability

This article is based on analysis originally published at Forbes.com, attributed to Moor Insights & Strategy.

APIs Are Everywhere — and Largely Unprotected

Application Programming Interfaces (APIs) are the connective tissue of modern software. They allow applications, microservices, mobile apps, and data platforms to communicate with each other. Yet despite their central role in every digital product, API security remains one of the most consistently underestimated attack surfaces in DevOps.

According to figures cited by Akamai, a large majority of Content Delivery Network (CDN) internet traffic is API traffic — meaning that vulnerabilities at the API layer represent a systemic risk to nearly all internet-connected services.

How APIs Are Used in DevOps

APIs serve a wide range of functions across modern engineering organizations:

• External integration: Banks, healthcare platforms, gaming companies, and e-commerce services expose APIs so that partners and customers can interact with their data and services.
• Internal modernization: DevOps teams use APIs to decompose monolithic legacy systems (ERP, CRM, SCM) into loosely coupled microservices and containers, enabling incremental modernization without full rewrites.
• Digital transformation: APIs are a foundational component of most digital transformation initiatives, enabling composable architectures and third-party integrations.

This ubiquity is precisely why API security cannot be treated as an afterthought. A single insecure API endpoint can expose the entire downstream system it serves.

Common API Security Vulnerabilities

Many API vulnerabilities stem from gaps in developer knowledge or inadequate security review processes. The OWASP API Security Top 10 documents the most critical classes of risk. Several recurring weaknesses include:

• Confusion between authentication and authorization: Authentication verifies who a caller is; authorization determines what they are permitted to do. Conflating these two concepts leads to broken access control — one of the most common and dangerous API flaws.
• Security misconfigurations: Default settings, overly permissive CORS policies, missing rate limiting, and exposed debug endpoints frequently make it into production.
• Insufficient logging and monitoring: Without visibility into API traffic patterns, teams cannot detect anomalous behavior, enumerate abuse, or reconstruct the chain of events after an incident.
• Insecure open-source dependencies: APIs often incorporate third-party libraries pulled from public repositories. Unvetted or outdated packages introduce vulnerabilities that developers may not be aware of.
• Lack of input validation: Failing to validate and sanitize API inputs opens the door to injection attacks and data manipulation.

A Real-World Example: API Exploitation in a Digital Payment System

The original Forbes analysis described a case involving Zelle, a peer-to-peer digital payment service widely integrated with U.S. banks. The attack chain illustrates how a weakness at the API integration layer can enable serious financial fraud:

1. Attackers gained full control of a victim’s email account.
2. Using that email access, they triggered credential reset flows — changing PINs, user IDs, and passwords via email and voice verification channels.
3. Attackers registered their own identities and biometrics on their own devices, effectively enrolling themselves as the account owner.
4. They exploited the API integration between Zelle and the victim’s financial institution to transfer funds — in increments under reporting thresholds — to attacker-controlled email addresses.

This type of attack is particularly difficult to detect and reverse. The fraud exploits the gap between a bank’s internal fraud controls and a third-party service’s API, an area where ownership and monitoring are often unclear. Because Zelle transfers are designed to feel like cash, they are hard for consumers to recover and hard for banks to trace.

DevOps Implications: Securing the API Integration Layer

For DevOps and platform engineering teams, this kind of incident highlights several operational responsibilities:

• Treat third-party API integrations as a trust boundary. Any external service your platform integrates with is a potential attack surface. Audit the security posture of third-party APIs before connecting them to your systems.
• Enforce least-privilege authorization at every API endpoint. Each service-to-service call should carry only the permissions it strictly requires, and those permissions should be validated server-side on every request.
• Implement rate limiting and anomaly detection. Unusual transfer patterns, high-frequency calls, and out-of-hours activity should trigger alerts. API gateways (Kong, AWS API Gateway, Apigee, etc.) can enforce these controls centrally.
• Require MFA for account actions with financial or access consequences. Credential resets, device registrations, and payment enrollments should require a second factor that cannot be satisfied by email alone.
• Log API calls comprehensively and review them. Without structured, queryable logs, post-incident forensics are nearly impossible. Use a SIEM or centralized logging platform to correlate API activity across services.
• Conduct regular API security testing. Automated DAST tools (e.g., OWASP ZAP, Burp Suite) and manual penetration testing should be part of your secure SDLC, not a one-off activity.

Consumer-Level Protections

While the primary responsibility for API security lies with the organizations building and operating these systems, end users can take steps to reduce their personal exposure:

• Use strong, unique passwords for each service. A password manager simplifies this significantly. Avoid patterns based on personal information (birthdays, names, anniversaries).
• Enable multi-factor authentication (MFA) on all accounts, especially email, banking, and payment platforms. Prefer authenticator apps or hardware keys over SMS-based MFA where possible.
• Understand your bank’s fraud recovery policy. Peer-to-peer payment fraud is often not covered in the same way as traditional card fraud. Know what you are entitled to before you need it.
• Opt out of automatic third-party service enrollment. If your bank automatically enrolls you in services like Zelle, request to be unenrolled or confirm enrollment settings explicitly.
• Be cautious with phishing vectors. Attackers targeting payment API weaknesses often initiate attacks through email or phone phishing to capture credentials first.

The Broader Security Picture

API security is not a niche concern — it is a foundational requirement for any organization running modern software. As the adoption of microservices, cloud-native architectures, and third-party integrations accelerates, the API attack surface expands proportionally. The shift to remote work has compounded this risk by moving employees and their devices outside corporate network perimeters, making API-level controls even more critical.

The question facing most organizations is not whether an API-related breach will occur, but whether they have the visibility and controls in place to detect it quickly and limit the damage. Treating API security as a first-class engineering concern — built into design, development, testing, and operations — is the most reliable path to reducing that risk.

Disclosure: The original Forbes article was authored by an analyst at Moor Insights & Strategy. The firm has provided research, analysis, advising, and/or consulting to companies across the technology industry. This rewritten version is for editorial and educational purposes.