A new attack method can be used to circumvent web application firewalls (WAFs) of various vendors and infiltrate systems, potentially enabling attackers to gain access to sensitive business and customer information.
Web application firewalls are a key line of defence to help filter, monitor, and block HTTP(S) traffic to and from a web application, and safeguard against attacks such as cross-site forgery, cross-site-scripting (XSS), file inclusion, and SQL injection (SQLi).
The generic bypass “involves appending JSON syntax to SQL injection payloads that a WAF is unable to parse,” Claroty researcher Noam Moshe said. “Most WAFs will easily detect SQLi attacks, but prepending JSON to SQL syntax left the WAF blind to these attacks.”
The industrial and IoT cybersecurity company said its technique successfully worked against WAFs from vendors like Amazon Web Services (AWS), Cloudflare, F5, Imperva, and Palo Alto Networks, all of whom have since released updates to support JSON syntax during SQL injection inspection.
images from Hacker News