CWE-94 Code Injection

Description

Code Injection

Reference: https://cwe.mitre.org/data/definitions/94.html

OWASP Category: A03:2021 – Injection

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Vulnerable Pattern

❌ Example 1: Vulnerable Pattern

// VULNERABLE: User input executed as code
ScriptEngine engine = new ScriptEngineManager().getEngineByName("JavaScript");
engine.eval(userScript);

Why it's vulnerable: This pattern is vulnerable to Code Injection

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Deterministic Fix

✅ Secure Implementation: Secure Implementation

// SECURE: Avoid dynamic code execution
// Use predefined operations instead of user-provided scripts
Map<String, BiFunction<Object, Object, Object>> operations = Map.of(
    "add", (a, b) -> ((Number)a).doubleValue() + ((Number)b).doubleValue()
);
if (operations.containsKey(userOperation)) {
    return operations.get(userOperation).apply(a, b);
}

Why it's secure: Implements proper protection against Code Injection

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Detection Pattern

Look for these patterns in your codebase:

# Find ScriptEngine eval
grep -rn "ScriptEngine.*eval\\|engine.eval" --include="*.java"

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Remediation Steps

1. Never execute user-provided code directly

2. Use whitelisted operations/functions instead of dynamic scripts

3. If scripting is required, use sandboxed environments

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Key Imports

import java.util.function.BiFunction;

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Verification

After remediation:

• Run SAST scanner to confirm vulnerability is resolved

• Review all instances of the vulnerable pattern

• Add unit tests that verify the secure implementation

• Check for similar patterns in related code

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Trigger Examples

Fix CWE-94 vulnerability
Resolve Code Injection issue
Secure this Java code against code injection
SAST reports CWE-94

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Common Vulnerable Locations

Layer	Files	Patterns

| Controller | *Controller.java | User input handling |

| Service | *Service.java | Business logic |

| Repository | *Repository.java | Data access |

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References

• CWE-94: Code Injection

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Source: Generated by Java CWE Security Skills Generator Last Updated: 2026-03-07