CVE-2018-20834

A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• https://access.redhat.com/errata/RHSA-2019:1821
• https://github.com/npm/node-tar/commit/7ecef07da6a9e72cc0c4d0c9c6a8e85b6b52395d
• https://github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8
• https://github.com/npm/node-tar/commits/v2.2.2
• https://github.com/npm/node-tar/compare/58a8d43...a5f7779
• https://hackerone.com/reports/344595
• https://nvd.nist.gov/vuln/detail/CVE-2018-20834
• https://access.redhat.com/errata/RHSA-2019:1821
• https://github.com/npm/node-tar/commit/7ecef07da6a9e72cc0c4d0c9c6a8e85b6b52395d
• https://github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8
• https://github.com/npm/node-tar/commits/v2.2.2
• https://github.com/npm/node-tar/compare/58a8d43...a5f7779
• https://hackerone.com/reports/344595
• https://nvd.nist.gov/vuln/detail/CVE-2018-20834