CVE-2021-43519 : Exploit Details and Defense Strategies

A stack overflow vulnerability in Lua Interpreter 5.1.0 to 5.4.4 can lead to a Denial of Service attack when processing specially crafted script files.

Understanding CVE-2021-43519

This CVE involves a critical stack overflow issue in the Lua Interpreter, potentially enabling attackers to disrupt services through malicious script files.

What is CVE-2021-43519?

This vulnerability within the Lua Interpreter versions 5.1.0 to 5.4.4 allows threat actors to trigger a Denial of Service attack by exploiting the lua_resume function in the ldo.c file.

The Impact of CVE-2021-43519

The vulnerability poses a severe security risk as attackers can easily disrupt services by causing a stack overflow in the Lua Interpreter, leading to service unavailability.

Technical Details of CVE-2021-43519

This section delves deeper into the technical aspects of the CVE.

Vulnerability Description

The vulnerability occurs in the lua_resume function of the ldo.c file in Lua Interpreter 5.1.0 to 5.4.4, allowing threat actors to exploit it for a Denial of Service attack.

Affected Systems and Versions

Affected systems: All systems running Lua Interpreter versions 5.1.0 to 5.4.4
Affected versions: Lua Interpreter 5.1.0 to 5.4.4

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious script files that trigger a stack overflow in the lua_resume function, causing a Denial of Service.

Mitigation and Prevention

Protect your systems from this vulnerability by taking the following steps:

Immediate Steps to Take

Update Lua Interpreter to a non-vulnerable version.
Implement file input validation to prevent the execution of malicious scripts.

Long-Term Security Practices

Regularly monitor and audit Lua script execution for unusual activities.
Employ strong input validation mechanisms to thwart potential exploitation attempts.

Patching and Updates

Ensure timely updates and patches for the Lua Interpreter to address this vulnerability.