CVE-2021-41035 – This vulnerability in Eclipse Openj9 allows att... (How to Fix)

Q: What is the severity of CVE-2021-41035?

CVE-2021-41035 has a CVSS score of 9.8 (CRITICAL). This vulnerability in Eclipse Openj9 allows attackers to bypass Java access controls by using MethodHandles to invoke interface methods that should be inaccessible. This affects applications running on vulnerable Openj9 JVM versions, potentially enabling privilege escalation or code execution.

📋 TL;DR

This vulnerability in Eclipse Openj9 allows attackers to bypass Java access controls by using MethodHandles to invoke interface methods that should be inaccessible. This affects applications running on vulnerable Openj9 JVM versions, potentially enabling privilege escalation or code execution.

💻 Affected Systems

Products:

Eclipse Openj9

Versions: All versions before 0.29.0

Operating Systems: All platforms running Openj9

Default Config Vulnerable: ⚠️ Yes

Notes: Affects any Java application running on vulnerable Openj9 JVM versions.

📦 What is this software?

Openj9 by Eclipse

View all CVEs affecting Openj9 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full system compromise through arbitrary code execution, privilege escalation, or bypassing security sandboxes in Java applications.

🟠

Likely Case

Application-level privilege escalation allowing attackers to access restricted data or functionality within vulnerable Java applications.

🟢

If Mitigated

Limited impact if applications don't use MethodHandles extensively or have additional security layers.

🌐 Internet-Facing: HIGH - Web applications using vulnerable Openj9 could be exploited remotely.

🏢 Internal Only: HIGH - Internal applications could be exploited by authenticated users or through other attack vectors.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires understanding of Java MethodHandles and access control mechanisms.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 0.29.0 and later

Vendor Advisory: https://bugs.eclipse.org/bugs/show_bug.cgi?id=576395

Restart Required: Yes

Instructions:

1. Download Openj9 version 0.29.0 or later. 2. Replace existing Openj9 JVM with patched version. 3. Restart all Java applications using the updated JVM.

🔧 Temporary Workarounds

Disable MethodHandles usage

all

Restrict or monitor usage of MethodHandles in application code

No direct commands - requires code review and modification

🧯 If You Can't Patch

Implement strict network segmentation to isolate vulnerable systems
Deploy runtime application security protection (RASP) to detect exploitation attempts

🔍 How to Verify

Check if Vulnerable:

Check Openj9 version: java -version should show Openj9 version. If version is below 0.29.0, system is vulnerable.

Check Version:

java -version | grep -i openj9

Verify Fix Applied:

After patching, verify java -version shows Openj9 0.29.0 or higher.

📡 Detection & Monitoring

Log Indicators:

Unusual MethodHandles usage patterns
SecurityManager access violation logs
IllegalAccessError exceptions

Network Indicators:

Unusual outbound connections from Java processes
Suspicious network traffic patterns

SIEM Query:

source="java.log" AND ("MethodHandles" OR "IllegalAccessError")

📊 Metadata

CVE ID: CVE-2021-41035

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-250

Published: October 25, 2021

Last Updated: November 21, 2024

🔗 References

https://bugs.eclipse.org/bugs/show_bug.cgi?id=576395 Vendor Advisory
https://github.com/eclipse-openj9/openj9/pull/13740 Patch,Third Party Advisory
https://gitlab.eclipse.org/eclipsefdn/emo-team/emo/-/issues/104 Vendor Advisory
https://security.netapp.com/advisory/ntap-20240621-0006/
https://bugs.eclipse.org/bugs/show_bug.cgi?id=576395 Vendor Advisory
https://github.com/eclipse-openj9/openj9/pull/13740 Patch,Third Party Advisory
https://gitlab.eclipse.org/eclipsefdn/emo-team/emo/-/issues/104 Vendor Advisory
https://security.netapp.com/advisory/ntap-20240621-0006/

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🔗 Related Vulnerabilities

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