CVE-2017-9841: Drupal Sites Exploited Using PHPUnit Vulnerability in Mailchimp Modules (PSA-2019-0904)

Satnam Narang

Attackers are leveraging a vulnerability patched nearly three years ago to target Drupal sites.

Background

On September 4, Drupal published PSA-2019-09-04, a public service announcement (PSA) for a vulnerability in a third-party library in a Drupal module that’s being actively exploited in the wild.

Analysis

CVE-2017-9841 is a code injection vulnerability in PHPUnit, a PHP unit testing framework. The PHPUnit library is part of the Mailchimp and Mailchimp E-Commerce modules in Drupal which, according to their modules pages, are currently used by over 25,000 sites combined.

In June 2017, a Twitter account called “vulnbusters” was created and published an advisory for the vulnerability on their now-defunct website, which is available through the Internet Archive’s Wayback Machine here.

The advisory identifies the vulnerability within the /phpunit/src/Util/PHP/eval-stdin.php file through its use of the php://input wrapper. Patched versions of PHPUnit use the php://stdin wrapper instead. An unauthenticated attacker could exploit this vulnerability by sending an HTTP POST request to a web server containing the vulnerable eval-stdin.php file, leading to arbitrary code execution.

Previous versions of PHPUnit contained the code injection vulnerability which, according to the Vulnbusters advisory page, was unknowingly patched in November 2016 in PHPUnit version 4.8.28 and version 5.6.3 to address issues with insulated tests using phpdbg.

In February 2018, an issue was filed on the Mailchimp project on Drupal from a user who was contacted by their hosting provider, indicating that the eval-stdin.php on their web server was malicious. A different user, who commented on the same issue in May 2018, also received the same feedback from their hosting provider. Separately, in February 2018, Kevin Beaumont (@GossiTheDog) found attackers were targeting a Drupal honeypot attempting to exploit CVE-2017-9841.

Outside of Drupal, CVE-2017-9841 has also been found in WordPress plugins, such as the Jekyll Exporter plugin, as well as MediaWiki and open source learning platform Moodle.

Proof of concept

A proof-of-concept (PoC) was originally published in the Vulnbusters advisory from June 2017.

Solution

As previously mentioned, CVE-2017-9841 was patched in PHPUnit back in November 2016. The vulnerability affected specific versions of PHPUnit, which are referenced in the table below.

Vulnerable PHPUnit Versions Fixed PHPUnit Versions 4.8.19 - 4.8.27 4.8.28 or later 5.0.10 - 5.6.2 5.6.3 or later

For the Mailchimp and Mailchimp E-Commerce modules, version 1.0.7 or below for the Mailchimp API for PHP is considered vulnerable. The Drupal Security team notes even if Drupal customers had previously installed these modules, there may still be artifacts left over from the installation on the web server. Vulnerable servers may have the eval-stdin.php. If the file exists and it references the php://input wrapper instead of the php://stdin wrapper, then the server is vulnerable to CVE-2017-9841.

CVE-2017-9841: Drupal Sites Exploited Using PHPUnit Vulnerability in Mailchimp Modules (PSA-2019-0904)

Identifying affected systems

A list of Tenable plugins to identify this vulnerability will appear here as they’re released.

Get more information

Join Tenable's Security Response Team on the Tenable Community.

Learn more about Tenable, the first Cyber Exposure platform for holistic management of your modern attack surface.

Get a free 60-day trial of Tenable.io Vulnerability Management.

Read more >

Published on Sep 5, 2019

People also viewed

Business Cost Analyst - Cloud Infrastructure

San Jose California United States E Santa Clara St., San Jose, California, United States, 95113 Engineering Engineering
Your Role:Tenable is seeking a Business Cost Analyst of Cloud Infrastructure with strong MS Excel experience to assess, analyze and compile current costs and potentially determine initiatives to reduce and improve our cloud infrastructure cost for...

Professional Services Engagement Manager

Singapore Singapore Singapore North Bridge Road, Parkview Square, Singapore, 188788 Professional Services Professional Services
Your Role:The Professional Services Engagement Manager assists in the professional services business development and oversees the delivery of projects. The Professional Services Engagement Manager’s roles include tactical project management oversi...

UX Designer

Columbia Maryland United States Columbia Gateway Drive, Columbia, Maryland, United States, 21046 Engineering Engineering
Your Role:Tenable is looking for an extraordinary Senior UX Designer to join our team. Our group is chartered with creating the next generation of security products while at the same time pioneering unprecedented user experience in the digital sec...

Commercial Territory Manager - West

Columbia Maryland United States Columbia Gateway Drive, Columbia, Maryland, United States, 21046 Sales Sales
Your Role:The Commercial Territory Manager will meet and exceed quarterly sales quota by developing new opportunities within specific geographical territory.  Researching and identifying potential accounts; outbound cold calling to soliciting new ...

Senior Software Engineer (Java & Kotlin)

San Jose California United States E Santa Clara St., San Jose, California, United States, 95113 Engineering Engineering
Your Role:Tenable is looking for a Senior Software Engineer to join the Lumin product development team. As a Sr. Software Engineer you will drive projects end-to-end, collaborate on product requirements with Product Managers, architect and impleme...

Public Sector Channel Manager - Distribution

Reston Virginia United States Reston, Virginia, United States Channel Sales Sales
Your Role:The Public Sector Channel Manager-Distribution is responsible for establishing and managing relationships with the Distribution Partner(s).  The CM-Disty will act as a sales liaison between distributor and Tenable Channel Manager personn...

We have big plans for continued global growth, and we’re looking for people who are creative, flexible and dedicated to helping us build something great – something that matters.