CVE-2021-32761 Explained : Impact and Mitigation

In this article, we will explore the details of CVE-2021-32761, a vulnerability impacting Redis versions that can lead to integer overflow issues on 32-bit systems and potential remote code execution.

Understanding CVE-2021-32761

This section provides insights into the nature of the vulnerability and its potential impact on Redis systems.

What is CVE-2021-32761?

CVE-2021-32761 involves an integer overflow vulnerability related to Redis

*BIT*

commands on 32-bit systems, potentially leading to buffer overflow and remote code execution.

The Impact of CVE-2021-32761

The vulnerability poses a high severity risk, with a CVSS base score of 7.5. It can compromise the confidentiality, integrity, and availability of affected systems, requiring immediate attention.

Technical Details of CVE-2021-32761

This section delves into the specific technical aspects of the CVE, including the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability starts from Redis version 2.2 and continues up to versions 5.0.13, 6.0.15, and 6.2.5. It arises from an out-of-bounds read and integer overflow, allowing attackers to trigger buffer overflow and potentially execute remote code.

Affected Systems and Versions

Redis versions >= 2.2 and < 5.0.13, >= 6.0.0 and < 6.0.15, and >= 6.2.0 and < 6.2.5 on 32-bit systems are vulnerable to this issue.

Exploitation Mechanism

By manipulating the

proto-max-bulk-len

configuration parameter and crafting specific bit commands, attackers can exploit this vulnerability on Redis 32-bit systems, potentially leading to heap corruption and remote code execution.

Mitigation and Prevention

This section outlines the necessary steps to mitigate and prevent exploitation of CVE-2021-32761 on Redis systems.

Immediate Steps to Take

It is crucial to apply patches available in Redis versions 5.0.13, 6.0.15, and 6.2.5 to address this vulnerability. Additionally, restricting users from modifying the

proto-max-bulk-len

parameter via ACL can provide a temporary workaround.

Long-Term Security Practices

In the long term, following security best practices, regularly updating Redis installations, and implementing strong access controls can help enhance the overall security posture.

Patching and Updates

Stay vigilant for security advisories and promptly apply relevant patches released by Redis to ensure ongoing protection against potential vulnerabilities.