CVE-2021-45707 : Vulnerability Insights and Analysis

An issue was discovered in the nix crate for Rust versions 0.16.0 through 0.22.2, leading to an out-of-bounds write vulnerability in unistd::getgrouplist.

Understanding CVE-2021-45707

This CVE involves a vulnerability in the nix crate for Rust that could be exploited by a user in more than 16 /etc/groups groups.

What is CVE-2021-45707?

The CVE-2021-45707 vulnerability occurs in versions 0.16.0 and later before 0.20.2, 0.21.x before 0.21.2, and 0.22.x before 0.22.2 of the nix crate for Rust. It allows an out-of-bounds write when a user belongs to over 16 /etc/groups groups.

The Impact of CVE-2021-45707

This vulnerability could be leveraged by a malicious actor to write out of bounds, potentially leading to a denial of service (DoS) or arbitrary code execution.

Technical Details of CVE-2021-45707

The technical details shed light on the specifics of the vulnerability.

Vulnerability Description

The flaw in unistd::getgrouplist allows an out-of-bounds write due to inadequate bounds checking for users in multiple /etc/groups groups.

Affected Systems and Versions

Versions 0.16.0 through 0.22.2 of the nix crate for Rust are affected.

Exploitation Mechanism

By having a user in more than 16 /etc/groups groups, an attacker can trigger the out-of-bounds write vulnerability in unistd::getgrouplist.

Mitigation and Prevention

Protecting systems from CVE-2021-45707 involves taking immediate and long-term security measures.

Immediate Steps to Take

Update the nix crate to a version beyond 0.22.2.
Monitor system logs for any unusual activity that could indicate exploitation.
Implement least privilege access controls to limit the impact of potential attacks.

Long-Term Security Practices

Regularly audit and review code for vulnerabilities like out-of-bounds writes.
Conduct security training for developers on secure coding practices.

Patching and Updates

Apply patches released by the nix crate maintainers promptly to mitigate the CVE-2021-45707 vulnerability.