CVE-2018-20482 : Vulnerability Insights and Analysis

CVE-2018-20482 was published on December 26, 2018, and affects GNU Tar up to version 1.30. The vulnerability involves mishandling file shrinkage when using the --sparse option, potentially leading to a denial of service attack. This CVE allows local users to trigger an infinite read loop in the sparse_dump_region function by modifying a file intended for archiving by another user's process.

Understanding CVE-2018-20482

This section provides insights into the nature and impact of the CVE.

What is CVE-2018-20482?

CVE-2018-20482 is a vulnerability in GNU Tar versions up to 1.30 that mishandles file shrinkage when the --sparse option is utilized. This flaw can be exploited by local users to cause a denial of service by creating an infinite read loop in the sparse_dump_region function.

The Impact of CVE-2018-20482

The vulnerability allows local users to disrupt the operation of GNU Tar, potentially leading to a denial of service condition. By manipulating files intended for archiving by privileged processes, attackers can trigger an infinite read loop, affecting system stability and performance.

Technical Details of CVE-2018-20482

This section delves into the technical aspects of the CVE.

Vulnerability Description

The flaw in GNU Tar versions up to 1.30 allows local users to exploit file shrinkage mishandling with the --sparse option, leading to a denial of service through an infinite read loop in the sparse_dump_region function.

Affected Systems and Versions

Product: GNU Tar
Vendor: N/A
Versions affected: Up to version 1.30

Exploitation Mechanism

Attackers can exploit this vulnerability by modifying files designated for archiving by other privileged processes, such as system backups running with root privileges. This manipulation triggers the infinite read loop in the sparse_dump_region function.

Mitigation and Prevention

Protecting systems from CVE-2018-20482 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update GNU Tar to a patched version that addresses the vulnerability.
Monitor system logs for any unusual file access or read loop activities.

Long-Term Security Practices

Implement the principle of least privilege to restrict user access to critical files.
Regularly review and update file permissions to prevent unauthorized modifications.

Patching and Updates

Apply security patches provided by GNU Tar to fix the vulnerability.
Stay informed about security advisories and updates from relevant vendors and security communities.