CVE-2021-44964 : Exploit Details and Defense Strategies

A vulnerability in the Lua interpreter 5.4.0~5.4.3 could allow attackers to perform Sandbox Escape through a crafted script file.

Understanding CVE-2021-44964

This CVE relates to a use after free vulnerability in the garbage collector and finalizer of lgc.c in Lua interpreter versions 5.4.0 to 5.4.3.

What is CVE-2021-44964?

This vulnerability enables attackers to execute unauthorized code and break out of the Lua interpreter's sandbox protection, potentially leading to further malicious actions.

The Impact of CVE-2021-44964

Exploitation of this vulnerability could result in Sandbox Escape, allowing attackers to run arbitrary code outside of the intended Lua script execution environment.

Technical Details of CVE-2021-44964

This section delves into the specific technical aspects of the vulnerability.

Vulnerability Description

The use after free in the garbage collector and finalizer of lgc.c in Lua interpreter 5.4.0~5.4.3 allows malicious actors to perform Sandbox Escape by leveraging a specially crafted script file.

Affected Systems and Versions

Vulnerable Versions: Lua interpreter 5.4.0 to 5.4.3
Systems: All systems running the affected versions of the Lua interpreter are susceptible to this vulnerability.

Exploitation Mechanism

Hackers can exploit this vulnerability by providing a malicious Lua script file, triggering the use after free condition in the garbage collector and finalizer of lgc.c, consequently allowing them to escape the sandbox.

Mitigation and Prevention

Understanding how to mitigate and prevent the exploitation of CVE-2021-44964 is crucial for maintaining system security.

Immediate Steps to Take

Update to a patched version of the Lua interpreter to mitigate the vulnerability.
Avoid running untrusted Lua scripts from unknown sources.

Long-Term Security Practices

Conduct regular security audits to identify and address potential vulnerabilities in the system.
Implement sandboxing mechanisms to limit the impact of script execution.

Patching and Updates

Stay informed about security updates for the Lua interpreter and promptly apply patches to secure the system.