WAF Bypasses

Encoding Evasion: Use URL, Unicode, Base64, or other encodings to disguise payloads.

HTTP Parameter Pollution: Manipulate parameters to exploit the way the WAF processes multi-instance parameters. (One of my favourite techniques!)

Session Splicing: Divide the attack into multiple requests or sessions to disrupt the WAF's ability to correlate the events.

Verb Tampering: Change the HTTP method (GET, POST, HEAD, etc.) to an unconventional one that the WAF might not inspect.

Path Obfuscation: Include irrelevant path information that gets ignored by the server but confuses the WAF (like using directory traversal techniques).

Query String Manipulation: Alter the query string with special characters or payloads that might be overlooked by the WAF.

Header Manipulation: Modify HTTP headers such as User-Agent, Referer, or custom headers in ways that are not expected.

Cookie Poisoning: Inject payloads into cookie values which may not be inspected or properly sanitized by the WAF.

Content-Type Evasion: Use unusual or mismatched content-types in the HTTP header to bypass checks that are content-type specific.

Extension Manipulation: Changing file extensions or using obscure ones to evade filters that inspect file names.

Protocol-Level Evasion: Utilize discrepancies in protocol implementations (like ambiguous requests) that may be differently interpreted by the WAF and the target web server.

Attack Obfuscation with Legitimate Requests: Mix in legitimate traffic with the attack traffic to reduce the anomaly score that might otherwise trigger the WAF.

Bypassing with JavaScript: Use JavaScript to construct the final payload in the client-side browser, which may not be executed or recognized by the WAF.

Using Comment Injection: Place comments within SQL statements or scripts to disrupt signature detection.

Utilizing Server-Side Request Forgery (SSRF): Exploit the server's functionality to make requests that bypass the WAF's rules.

Timing Attacks: Execute actions with delays, leveraging the fact that some WAFs have a time window for rule execution.

Ruleset Flaws: Exploit known weaknesses in the rulesets employed by popular WAFs, which are sometimes documented by security researchers.