diff --git a/rules/REQUEST-920-PROTOCOL-ENFORCEMENT.conf b/rules/REQUEST-920-PROTOCOL-ENFORCEMENT.conf
index fbc908cda..b0b8f1792 100644
--- a/rules/REQUEST-920-PROTOCOL-ENFORCEMENT.conf
+++ b/rules/REQUEST-920-PROTOCOL-ENFORCEMENT.conf
@@ -1130,7 +1130,7 @@ SecRule REQUEST_HEADERS_NAMES "@rx ^.*$" \
     severity:'CRITICAL',\
     setvar:'tx.header_name_%{tx.0}=/%{tx.0}/',\
     chain"
-    SecRule TX:/^HEADER_NAME_/ "@within %{tx.restricted_headers}" \
+    SecRule TX:/^header_name_/ "@within %{tx.restricted_headers}" \
         "setvar:'tx.anomaly_score_pl1=+%{tx.critical_anomaly_score}'"