Arbitrary file disclosure in PHPMailer

1) Information disclosure

EUVDB-ID: #VU4756

Risk: Medium

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-5223

CWE-ID: CWE-200 - Information exposure

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to obtain access to potentially sensitive information.

The vulnerability exists in PHPMailer before 5.2.22 when handling HTML documents using msgHTML() method. A remote attacker can create a specially crafted message, containing relative links to images withing message and attach arbitrary local file to e-mail message.

Successful exploitation of this vulnerability may allow an attacker to send out arbitrary system files as email attachments.

Mitigation

Update to version 5.2.22.

Vulnerable software versions

PHPMailer: 5.2 - 5.2.21

External links

http://kalilinux.co/2017/01/12/phpmailer-cve-2017-5223-local-information-disclosure-vulnerability-an...
http://github.com/PHPMailer/PHPMailer/blob/master/SECURITY.md

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.