Description
WordPress is prone to a Denial of Service vulnerability which can be exploited by malicious people to cause the affected website to consume memory and CPU resources, thus denying service to legitimate users. WordPress versions 4.0.x ranging from 4.0 and up to (and including) 4.0.22 are vulnerable.
Remediation
Evaluate and apply the suggested patch
References
https://baraktawily.blogspot.ro/2018/02/how-to-dos-29-of-world-wide-websites.html
https://www.youtube.com/watch?v=nNDsGTalXS0
https://github.com/Quitten/WordPress/blob/master/wp-dos-patch.sh
https://www.exploit-db.com/exploits/43968/
https://packetstormsecurity.com/files/146249/WordPress-Core-Denial-Of-Service.html
https://www.rastating.com/protecting-wordpress-against-cve-2018-6389/
Related Vulnerabilities
WordPress Plugin PhastPress Open Redirect (1.110)
WordPress Plugin BackWPup Cross-Site Scripting (3.0.12)
WordPress Plugin ThirstyAffiliates Affiliate Link Manager Cross-Site Scripting (3.9.2)
WordPress Plugin WP Spell Check Cross-Site Request Forgery (7.1.9)
WordPress Plugin Special Text Boxes Arbitrary File Upload (5.1.90)