You are an ethical hacker at Nexus Cybersecurity, contracted to perform a penetration test for...

String concatenation is the best match because the technique described is breaking a recognizable SQL keyword or payload into separate pieces so a signature-based WAF rule does not see the full malicious token in one continuous pattern. In CEH-aligned web application testing, many WAF detections rely on matching known strings such as UNION SELECT, OR 1=1, and other classic patterns. If an attacker can cause the database parser to interpret the same meaning while the input appears different at the inspection layer, the WAF may fail to match its rule and the payload can reach the backend.

The prompt explicitly says you “split the query into multiple parts” to avoid detection as “a single signature.” That is the core idea of concatenation-based evasion: represent the same instruction through separated fragments that are recombined or tolerated by the SQL parser, depending on the database and application behavior. This differs from in-line comments, which would typically insert comment markers inside keywords to break signatures while preserving parsing, and differs from hex encoding, which replaces characters or strings with hexadecimal representations. A null byte technique is usually associated with string-termination tricks in older contexts and does not align with splitting SQL keywords for WAF bypass.

Defensively, CEH guidance emphasizes that relying on WAF signatures alone is insufficient. Strong prevention requires parameterized queries, strict server-side input validation, least-privilege database accounts, and monitoring for anomalous query patterns and error behaviors even when obvious signatures are not present.