Mitigation Instructions for CVE-2020-28949

Written by CyRisk Vulnerability Management Team | Mar 22, 2023 3:24:56 PM

SUBJECT: CVE-2020-28949 PEAR Archive_Tar Deserialization of Untrusted Data Vulnerability

TECH STACK: PEAR Archive_Tar versions 1.4.0 and earlier.

DATE(S) ISSUED: 11/19/2020

CRITICALITY: HIGH

OVERVIEW:

CVE-2020-28949 is a vulnerability in the PEAR Archive_Tar software library that could allow an attacker to execute arbitrary code on a server running a vulnerable version of the software. PEAR Archive_Tar is a library used to create and extract tar (tape archive) files, which are a common format for storing and distributing groups of files.

The vulnerability is caused by a flaw in the way that PEAR Archive_Tar processes certain types of data, specifically tar files that contain serialized data. An attacker could exploit this flaw by creating a specially crafted tar file that, when processed by a vulnerable version of PEAR Archive_Tar, could execute arbitrary code on the server. The vulnerability affects PEAR Archive_Tar versions 1.4.0 and earlier.

NIST Description: Archive_Tar through 1.4.10 has :// filename sanitization only to address phar attacks, and thus any other stream-wrapper attack (such as file:// to overwrite files) can still succeed.

https://nvd.nist.gov/vuln/detail/CVE-2020-28949

THREAT INTELLIGENCE:

CISA has added CVE-2020-28949 to its Known Exploited Vulnerabilities Catalog, based on evidence that threat actors are actively exploiting the vulnerability. This vulnerability is a frequent attack vector for malicious cyber actors of all types and poses significant risk to the federal enterprise.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

NIST: NVD

Base Score: 7.8 HIGH

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

SOLUTION:

To patch the PEAR Archive_Tar Deserialization of Untrusted Data vulnerability (CVE-2020-28949), you will need to update to a version of the Archive_Tar library that addresses this issue. This vulnerability exists in versions of Archive_Tar prior to 1.4.4.

To update to the latest version of Archive_Tar, you can use the following steps:

Make sure you have the PEAR package manager installed on your system. If you don't have it installed, you can install it by running the following command:
sudo apt-get install php-pear
Upgrade the Archive_Tar library to the latest version by running the following command:
sudo pear upgrade Archive_Tar
Once the upgrade is complete, you can verify that you are running the latest version by running the following command:
pear list Archive_Tar

This should show you the version number of the Archive_Tar library that you have installed. Make sure that the version number is at least 1.4.4 to ensure that you are running a version that is not vulnerable to the Deserialization of Untrusted Data vulnerability.

It's also a good idea to make sure that your other PEAR packages are up to date by running the following command:

sudo pear upgrade-all

This will ensure that all of your PEAR packages are running the latest and most secure versions.

REFERENCES:

CONFIRM:https://www.drupal.org/sa-core-2020-013

DEBIAN:DSA-4817

URL:https://www.debian.org/security/2020/dsa-4817

FEDORA:FEDORA-2020-5271a896ff

URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NBYZSHYTIOBK6V7C4N7TP6KIKCRKLVWP/

FEDORA:FEDORA-2020-6f1079934c

URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KWM4CTMEGAC4I2CHYNJVSROY4CVXVEUT/

FEDORA:FEDORA-2020-d50d74d6f2