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CVE-2016-10045: Phpmailer Project: Remote code execution

CVE-2016-10045 is rated critical with a CVSS v3.1 base score of 9.8 and affects Phpmailer Project, along with 2 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

The isMail transport in PHPMailer before 5.2.20 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code by leveraging improper interaction between the escapeshellarg function and internal escaping performed in the mail function in PHP. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-10033.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
• Attack complexity: Low. No special conditions; the attack can be repeated reliably.
• Privileges required: None. No account or prior access is needed.
• User interaction: None. No action from any user is needed.
• Scope: Unchanged. Impact stays within the vulnerable component.
• Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
• Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
• Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-77: Improper Neutralization of Special Elements used in a Command

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Affected products

• Phpmailer Project: before 5.2.20
• WordPress: up to and including 4.7
• Joomla!: from 1.5.0 up to and including 3.6.5

References

• http://openwall.com/lists/oss-security/2016/12/28/1
• http://seclists.org/fulldisclosure/2016/Dec/81
• https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.20
• https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilities
• https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10045-Vuln-Patch-Bypass.html
• http://packetstormsecurity.com/files/140286/PHPMailer-Remote-Code-Execution.html
• http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html
• http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injection
• http://www.securityfocus.com/archive/1/539967/100/0/threaded
• http://www.securityfocus.com/bid/95130
• http://www.securitytracker.com/id/1037533
• https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html
• https://www.exploit-db.com/exploits/40969/
• https://www.exploit-db.com/exploits/40986/