SANS ISC: Critical security update: PHPMailer 5.2.20 (CVE-2016-10045) - SANS Internet Storm Center

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UPDATE: 28 DEC 2016 - Critical security update for CVE-2016-10045 please update again ASAP. This is in addition to CVE-2016-10033 as fixed in 5.2.18. You should update to 5.2.20 at a minimum.

Vulnerability: PHPMailer < 5.2.20 Remote Code Execution [CVE-2016-10033]

Severity: CRITICAL

ISC recommended action: Patch...now. This is a very popular application, left unpatched it will be exploited.

Finder: Dawid Golunski (@dawid_golunski), https://legalhackers.com

PHPMailer
"Probably the world's most popular code for sending email from PHP!
Used by many open-source projects: WordPress, Drupal, 1CRM, SugarCRM, Yii, Joomla! and many more"

Description
An independent research uncovered a critical vulnerability in PHPMailer that could potentially be used by (unauthenticated) remote attackers to achieve remote arbitrary code execution in the context of the web server user and remotely compromise the target web application.
To exploit the vulnerability an attacker could target common website components such as contact/feedback forms, registration forms, password email resets and others that send out emails with the help of a vulnerable version of the PHPMailer class.

https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html

Patching
The PHPMailer team has released update 5.2.18 to address this critical security finding.

Changelog: https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md

Clone or download: https://github.com/PHPMailer/PHPMailer

Russ McRee | @holisticinfosec

PoC
https://legalhackers.com/exploits/CVE-2016-10045/PHPMailer_RCE_exploit.pl

Fix (to version 5.2.18) brings another vuln - CVE-2016-10045
"CVE-2016-10045: Critical RCE vulnerability introduced in 5.2.18"
https://github.com/PHPMailer/PHPMailer/issues/924

Wordpress stated that it is not vulnerable to this....

"Presently, WordPress Core (and as a result, anything utilising wp_mail()) are unaffected by the recent disclosures, the vulnerabilities require the usage of a PHPMailer feature which WordPress & wp_mail() does not use. This applies to WordPress 4.7, 4.6.x, and all previous secure versions."

Src: https://core.trac.wordpress.org/ticket/37210

However, they do state that the PHPMailer library is shipped with WordPress and that they will update the library to latest with an upcoming release. Not sure why they ship releases with the library unless some part of the WordPress code uses bits of PHPMailer.

Also, the patch did not fix the vulnerability. You want to update to 5.2.20.

There appears to be an update for the update. Version 5.2.21 is current at the moment.