Update index.md

Author: danielledennis

articles/external-attack-surface-management/index.md

@@ -3,7 +3,7 @@ title: Overview
 description: Microsoft Defender External Attack Surface Management (Defender EASM) continuously discovers and maps your digital attack surface to provide an external view of your online infrastructure.
 author: danielledennis
 ms.author: dandennis
-ms.service: security
+ms.service: defender-easm
 ms.date: 07/14/2022
 ms.topic: conceptual
 ---