SB2017112913 - Multiple vulnerabilities in WordPress

Description

This security bulletin contains information about 4 secuirty vulnerabilities.

1) Insufficient randomization (CVE-ID: CVE-2017-17091)

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists in wp-admin/user-new.php script due to usage of a determinate substring in newbloguser key, which can be directly derived from the user ID. A remote attacker can guess the key and bypass intended access restrictions.

2) Cross-site scripting (CVE-ID: CVE-2017-17093)

The vulnerability allows a remote attacker to perform XSS attacks.

The vulnerability exists due to insufficient sanitization of the language attributes used on html elements in wp-includes/general-template.php script. A remote attacker can bypass implemented filters and execute arbitrary HTML and script code in victims browser in context of the vulnerable website.

3) Cross-site scripting (CVE-ID: CVE-2017-17094)

The vulnerability allows a remote attacker to perform XSS attacks.

The vulnerability exists due to insufficient sanitization of the attributes of enclosures in RSS and Atom feeds within wp-includes/feed.php script. A remote attacker can bypass implemented filters and execute arbitrary HTML and script code in victims browser in context of the vulnerable website.

4) Improper access control (CVE-ID: CVE-2017-17092)

The vulnerability allows a remote attacker to upload JavaScript files.

The vulnerability exists due to incorrectly implemented access restrictions in wp-includes/functions.php script, which allowed uploading of JavaScript files for users without unfiltered_html permissions. A remote authenticated attacker can upload malicious JavaScript file and perform XSS or spoofing attacks against website users.

Remediation

Install update from vendor's website.

References

• https://wordpress.org/news/2017/11/wordpress-4-9-1-security-and-maintenance-release/