Why have APIs become a top attack vector?
Unlike traditional web applications that present a user interface, application programming interfaces (APIs) expose raw functionality and direct data access points, creating an entirely different security paradigm. API attacks probe these digital doorways, with threat actors looking for opportunities to gain unauthorized access, steal data, or cause service disruptions.
Here’s why that’s a big problem (that’s only getting bigger!): The growth of microservices architecture has transformed how applications are built and deployed, meaning each microservice typically exposes multiple API endpoints. The result is a sprawling network of potential entry points that security teams must monitor and protect.
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In cloud environments, the risk isn’t just that an API is vulnerable – it’s how that vulnerability connects to sensitive data, over-permissive identities, and exposed networks. This context determines the real blast radius of an attack.
Considering how many shadow/zombie APIs there are, the value proposition for attackers is clear. They’re seen as an easy target, plus APIs frequently contain rich business logic and provide direct access to sensitive data. A successful API attack can yield far more valuable information than traditional web application exploits.
Common types of API attacks
Cloud-native applications have amplified challenges in API security. When services depend on each other, a vulnerability in one API can create a cascade of security risks throughout the entire system. A good first step toward creating fail‑proof systems is to understand the common attack vectors.
A go‑to resource for learning more is OWASP’s 2023 report on the top 10 API security risks. Below you’ll find common API attack vectors that can arise from the risks OWASP outlines.
1. Authorization and access control abuse
When an API accepts a request from an authenticated user without confirming that the user has the right to perform the action or reach the resource, your systems are ripe for authorization and access control abuse. Internal attackers or attackers with stolen credentials exploit these gaps to move beyond their intended privileges and gain sensitive data or access to system functions.
OWASP identifies three kinds of authorization abuse:
Broken object-level authorization (BOLA): Attackers change an object ID in the request path, query, or body. When the API fails to verify that the caller owns that object, the attacker can view, edit, or delete someone else’s data.
Broken function-level authorization (BFLA): A user calls an endpoint that performs a privileged action, such as altering a GET request to DELETE. If the API does not enforce role and action checks, the user gains abilities meant for administrators or other roles.
Broken object property level authorization (BOPLA): An endpoint returns or accepts updates to sensitive fields of an object, even though the caller should not see or modify them. This exposes personal data and allows hidden tampering with protected attributes.
2. Authentication attacks
Authentication attacks bypass the mechanisms an API uses to confirm a caller’s identity. Attackers exploit missing rate limits, weak password policies, or poor token handling to log in as someone else and move freely through the system.
These attacks are common because they are easy to execute, and they carry severe consequences. For example, the 2024 Snowflake data breach involved credential stuffing and stolen credentials obtained via malware to access customers' Snowflake instances, resulting in financial losses of millions across multiple customers.
OWASP’s actionable checklist helps you determine whether your API or microservice is vulnerable to authentication attacks.
3. Data exposure and enumeration
Without an up‑to‑date inventory of live APIs, versions, and hosts, businesses can fall victim to data exposure and enumeration risks. During these attacks, simple search queries, DNS sweeps, and version fuzzing can identify exposed endpoints, extract data, or let malicious actors move deeper into the environment.
Common data exposure and enumeration patterns include…
Shadow or zombie endpoints that never made it into the official inventory
Beta or debug versions left reachable from the internet after testing; these builds often lack authentication or rate limits, making enumeration and brute‑force attacks easy
Untracked external data flows where sensitive fields travel to third‑party APIs without visibility or controls, creating blind spots during incident response
Verbose error messages that reveal stack traces, system paths, or object names, giving attackers detailed clues for easier enumeration
4. Logic abuse
Logic abuse is possible when an API functions exactly as designed from a technical perspective but fails to account for how automated interactions can manipulate legitimate business processes for malicious gain.
Common logic‑abuse patterns include…
Skipping or reordering steps in a multi‑step workflow to bypass validation or payment checks
Reusing or stacking promo codes that were meant to be single‑use, draining marketing budgets
Hammering sensitive endpoints with high‑speed calls that lack proper rate limiting or sequence enforcement
Logic abuse is most commonly leveled against financial services, e‑commerce platforms, and e‑wallets because these systems offer instant cash‑out opportunities. For example, Revolut’s 2024 refund‑logic flaw let attackers exploit an automatic refund loophole and withdraw about $20 million.
5. Denial of service (DoS) or distributed denial of service (DDoS)
When attackers send enough requests to drain CPU, memory, or bandwidth, an API stops answering real users. These attacks are now so widespread that the terms “DoS” and “DDoS” have become part of everyday language:
A DoS attack overwhelms a target server by exhausting its resources. This can be done through high-volume request floods or by consuming resources in other ways. For example, a Slowloris attack consumes resources by holding connections open for extended periods.
A DDoS attack does the same but sources the flood from many compromised devices at once, dramatically amplifying the traffic and making it harder to block.
6. Injection attacks
An injection attack happens when an API accepts user input and passes it directly to a downstream interpreter without proper validation or sanitization. Attackers embed malicious strings that the backend forwards to a database engine, shell, or cloud function, allowing them to read or modify data, run commands, or pivot further into the environment.
Common exploitation patterns include…
SQL or NoSQL injection: An attacker can send a JSON payload like,
{
"username": "admin' OR 1=1 --",
"password": "anything"
}If the service concatenates this input into an SQL query, the single quote (‘) closes the intended string, OR 1=1 forces the condition to always be true, and -- comments out the rest of the statement, giving the attacker access to the entire table.
Command injection: If an API parameter such as
fileNameends up in a system call without quotation marks, a value likebackup.tar && rm -rf /runs extra commands on the host.Deserialization abuse: Binary or Base64 payloads reach a deserializer that loads attacker‑supplied classes, letting the attacker execute arbitrary code.
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Defend against API attacks in real-world environments
Effective defense starts with seeing attacks early and stopping them fast. Each breach now costs an average of $4.88 million, with attackers remaining undetected for about 194 days before the first alert. Those numbers make a clear business case: Continuous detection and prevention controls are not optional. They’re the cheapest way to avoid months of silent data loss and multi-million-dollar cleanup bills.
Shift-Left Controls – Stop vulnerabilities before they reach production:
Review API specifications for security requirements before deployment.
Enforce least-privilege permissions for each endpoint.
Apply strict input validation and schema enforcement in development.
Integrate policy checks directly into CI/CD pipelines.
Runtime & Detection Controls – Catch and contain threats in production:
Inspect every API call for abnormal methods, payload sizes, or schema drift.
Verify token signatures, expiry, and audience on every hop, rejecting missing or tampered headers.
Flag and redact PII, access keys, and internal IDs before they leave the service.
Monitor DNS, IP ranges, and ingress rules to identify new or forgotten endpoints exposed to the internet.
Alert on suspicious traffic patterns such as enumeration bursts, spikes in error codes, or requests from unusual geographies.
To be proactive about these measures, there are many API security testing tools available, such as OWASP ZAP for dynamic scans, Coraza WAF for basic filtering, Envoy for API gateways, and OPA for policy checks.
To support these measures, organizations often combine dynamic scanning, API gateway enforcement, web application firewalls, and policy-as-code checks. But operating multiple tools in isolation creates blind spots and alert fatigue.
Enter Wiz – the unified platform that delivers full API visibility, context-driven risk prioritization, and integrated remediation without the sprawl of disconnected point solutions.
How Wiz helps defend against API attacks
Wiz starts with complete visibility – discovering every API across your cloud estate, including shadow, zombie, and undocumented endpoints, without agents.
Next, Wiz correlates API configuration data, runtime traffic, identity permissions, and sensitive data locations in a unified risk graph. This context reveals which API risks have the largest blast radius, so security teams can focus on the most critical threats.
With Wiz, you can:
Discover every API endpoint across workloads, serverless functions, and managed services.
Detect sensitive data exposure, weak authentication, and unintended public access.
Monitor runtime traffic for anomalies, malicious patterns, and unusual geographies.
Prioritize risks by contextual blast radius, identity reach, and data classification.
Enable DevOps to remediate quickly through integrated workflows.
The result: Full API visibility, context-driven prioritization, and faster remediation – all from one unified platform instead of juggling multiple point tools.
See it in action: Request a personalized Wiz demo and find out how quickly you can uncover every API in your cloud, prioritize risks by business impact, and block attacks before they escalate.
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