REQUEST_HEADERS_NAMES
Description: Request header names
Syntax: REQUEST_HEADERS_NAMES
REQUEST_HEADERS_NAMES contains the names of all request headers (excluding values). Used to detect abnormal custom headers or whether header names themselves contain attack payloads.
Example:
# Detect abnormal characters in header names
SecRule REQUEST_HEADERS_NAMES "@rx [<>'\"]" \
"id:1012,phase:1,deny,msg:'Request header name contains illegal characters'"