This bypass technique targets Cross-Site Scripting (XSS) vulnerabilities and involves the use of multi-character HTML entities. These entities are special character sequences that are recognized by web browsers and can be used to confuse or bypass Web Application Firewalls (WAFs). By encoding parts of the payload using these entities, the WAF may fail to detect the malicious script, allowing an attacker to execute XSS attacks. This technique leverages the difference in how browsers and WAFs parse and interpret HTML entities. While the exact vendor of the WAF bypassed is not mentioned, this method can potentially affect any WAF that does not properly decode these multi-character HTML entities before filtering. The technique is shared to illustrate an advanced way to bypass WAF protections against XSS, which is crucial for security researchers and bug bounty hunters to understand. More comprehensive details are available through the referenced WhatsApp channel for those interested in the implementation and examples.
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