This tweet suggests a method to bypass a Web Application Firewall (WAF) using the JavaScript dynamic import() function. The technique might exploit the way some WAFs parse and analyze incoming web requests, especially those involving JavaScript code or JSON payloads. By using import(), an attacker could attempt to load malicious scripts dynamically, potentially evading signature-based or pattern-matching detection methods commonly used by WAFs. Since the vendor is unknown and no additional payload details are provided, the bypass technique might apply universally across multiple WAF products with similar detection weaknesses. Understanding the exact implementation and detection rules of the WAF can help prevent such bypass attempts. Security teams should consider testing for dynamic script loading techniques and enhance their WAF policies to detect and block unusual or suspicious use of import().
For more details, check out the original tweet here: https://twitter.com/ctbbpodcast/status/1934649863855099930