CVE-2019-11503 : Security Advisory and Response

Snap-confine as included in snapd before version 2.39 did not guard against symlink races during the chdir() operation, leading to a "cwd restore permission bypass."

Understanding CVE-2019-11503

This CVE entry describes a vulnerability in snap-confine, affecting versions prior to 2.39.

What is CVE-2019-11503?

The vulnerability in snap-confine allowed a bypass of permissions during the chdir() operation, potentially compromising the security of the current working directory.

The Impact of CVE-2019-11503

The vulnerability could be exploited to bypass permissions, posing a risk to the integrity and security of the system.

Technical Details of CVE-2019-11503

This section provides more in-depth technical information about the CVE.

Vulnerability Description

The previous version of snap-confine did not prevent symlink races during the chdir() operation, enabling a bypass of permissions for restoring the current working directory.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: Not applicable

Exploitation Mechanism

The vulnerability allowed malicious actors to manipulate symlink races during the chdir() operation, exploiting the flaw to bypass permissions.

Mitigation and Prevention

Mitigation strategies and steps to prevent exploitation of the vulnerability.

Immediate Steps to Take

Upgrade snapd to version 2.39 or newer to mitigate the vulnerability.
Monitor for any unauthorized changes to the current working directory.

Long-Term Security Practices

Regularly update snapd and other software components to patch known vulnerabilities.
Implement least privilege access controls to limit the impact of potential security breaches.

Patching and Updates

Apply patches and updates provided by snapd to address the vulnerability and enhance system security.