MATCHED_VAR_NAME
Description: Last matched variable name
Syntax: MATCHED_VAR_NAME
MATCHED_VAR_NAME contains the full name of the last variable that matched successfully. For example, if ARGS:username triggered the rule, the value of MATCHED_VAR_NAME would be “ARGS:username”. Used together with MATCHED_VAR to fully record both the location and content that triggered the rule.
Example:
# Log the matched variable name and value
SecRule ARGS "@detectXSS" \
"id:1064,phase:2,deny,msg:'XSS in %{MATCHED_VAR_NAME}: %{MATCHED_VAR}'"