CVE-2021-29939 : Exploit Details and Defense Strategies

An issue was discovered in the stackvector crate for Rust through 2021-02-19, leading to an out-of-bounds write in StackVec::extend due to specific anomalous data.

Understanding CVE-2021-29939

This CVE identifies a vulnerability in the stackvector crate for Rust that can be exploited to trigger an out-of-bounds write under certain conditions.

What is CVE-2021-29939?

CVE-2021-29939 refers to a flaw in the stackvector crate for Rust that allows for an out-of-bounds write operation when particular anomalous data is provided, potentially leading to unauthorized access or denial of service.

The Impact of CVE-2021-29939

Exploitation of this vulnerability could result in a malicious actor crafting specific inputs to trigger unexpected behavior, potentially compromising the integrity and security of Rust applications utilizing the affected crate.

Technical Details of CVE-2021-29939

The technical details of CVE-2021-29939 shed light on the nature of the vulnerability, the systems and versions affected, as well as the mechanism through which exploitation can occur.

Vulnerability Description

The vulnerability stems from an out-of-bounds write in StackVec::extend within the stackvector crate for Rust. This flaw is triggered when certain anomalous data is supplied, leading to potential unauthorized memory access beyond the limits.

Affected Systems and Versions

All versions of the stackvector crate for Rust through 2021-02-19 are impacted by CVE-2021-29939. Users are advised to take immediate action to mitigate the risks associated with this vulnerability.

Exploitation Mechanism

To exploit this vulnerability, an attacker would need to provide specific anomalous data to the StackVec::extend function within the stackvector crate. By exceeding the expected boundaries, an out-of-bounds write can be triggered, potentially resulting in a security breach.

Mitigation and Prevention

Addressing CVE-2021-29939 requires immediate action to reduce the risk of exploitation and enhance the overall security posture of Rust applications.

Immediate Steps to Take

Developers and users should update the stackvector crate to the latest non-vulnerable version to prevent exploitation of this out-of-bounds write vulnerability. Additionally, restricting access to applications utilizing the affected crate can help mitigate potential risks.

Long-Term Security Practices

Practicing secure coding principles, conducting regular security audits, and staying informed about the latest vulnerabilities and patches within the Rust ecosystem are essential for maintaining a proactive security posture.

Patching and Updates

Stay informed about security advisories and updates related to the stackvector crate in Rust. Promptly apply patches and security fixes to ensure that your applications are protected against known vulnerabilities.