diff --git a/build.gradle b/build.gradle
index 79e37cbcb..b57610b5d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -391,6 +391,7 @@ afterEvaluate {
             node.setting("plugins.security.check_snapshot_restore_write_privileges", "true")
             node.setting("plugins.security.restapi.roles_enabled", "[\"all_access\", \"security_rest_api_access\"]")
             node.setting("plugins.security.system_indices.enabled", "true")
+            node.setting("plugins.security.user_attribute_serialization.enabled", "true")
             // node.setting("plugins.security.system_indices.indices", "[\".opendistro-ism-config\"]")
         }
     }
diff --git a/src/main/resources/mappings/opendistro-ism-config.json b/src/main/resources/mappings/opendistro-ism-config.json
index 845bfe34c..68958f5e4 100644
--- a/src/main/resources/mappings/opendistro-ism-config.json
+++ b/src/main/resources/mappings/opendistro-ism-config.json
@@ -1,6 +1,6 @@
 {
   "_meta" : {
-    "schema_version": 24
+    "schema_version": 25
   },
   "dynamic": "strict",
   "properties": {
@@ -644,6 +644,10 @@
                   "type" : "keyword"
                 }
               }
+            },
+            "custom_attributes": {
+              "type": "object",
+              "dynamic": "true"
             }
           }
         }
diff --git a/src/main/resources/mappings/opensearch-control-center.json b/src/main/resources/mappings/opensearch-control-center.json
index 992f5da72..7ac36c824 100644
--- a/src/main/resources/mappings/opensearch-control-center.json
+++ b/src/main/resources/mappings/opensearch-control-center.json
@@ -1,6 +1,6 @@
 {
   "_meta": {
-    "schema_version": 1
+    "schema_version": 2
   },
   "dynamic": "strict",
   "properties": {
@@ -53,6 +53,10 @@
                   "type" : "keyword"
                 }
               }
+            },
+            "custom_attributes": {
+              "type": "object",
+              "dynamic": "true"
             }
           }
         },
diff --git a/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementRestTestCase.kt b/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementRestTestCase.kt
index 4a18d5c9a..ee9d4d2a5 100644
--- a/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementRestTestCase.kt
+++ b/src/test/kotlin/org/opensearch/indexmanagement/IndexManagementRestTestCase.kt
@@ -41,7 +41,7 @@ import javax.management.remote.JMXConnectorFactory
 import javax.management.remote.JMXServiceURL
 
 abstract class IndexManagementRestTestCase : ODFERestTestCase() {
-    val configSchemaVersion = 24
+    val configSchemaVersion = 25
     val historySchemaVersion = 7
 
     // Having issues with tests leaking into other tests and mappings being incorrect and they are not caught by any pending task wait check as
diff --git a/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt b/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt
index 2992a2ab2..a98158aee 100644
--- a/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt
+++ b/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt
@@ -88,6 +88,66 @@ abstract class IndexStateManagementRestTestCase : IndexManagementRestTestCase()
     val explainResponseOpendistroPolicyIdSetting = "index.opendistro.index_state_management.policy_id"
     val explainResponseOpenSearchPolicyIdSetting = "index.plugins.index_state_management.policy_id"
 
+    @Before
+    protected fun attemptAddAttributesToAdmin() {
+        val attrs = mapOf(
+            "department" to "engineering",
+            "env" to "itest",
+        )
+        try {
+            addAttributesToAdmin(attrs)
+        } catch (e: Exception) {
+            logger.warn("Skipping admin attribute setup: ${e.message}")
+        }
+    }
+
+    private fun buildAttributesPatch(op: String, attributes: Map<String, String>): StringEntity {
+        val payload = buildString {
+            append("[{\"op\":\"").append(op).append("\",\"path\":\"/attributes\",\"value\":{")
+            append(
+                attributes.entries.joinToString(",") { (k, v) ->
+                    "\"${k.replace("\"", "\\\"")}\":\"${v.replace("\"", "\\\"")}\""
+                },
+            )
+            append("}}]")
+        }
+        return StringEntity(payload, ContentType.APPLICATION_JSON)
+    }
+
+    /** Returns true if the PATCH succeeded (2xx), false if the route isn’t usable, and throws on fatal errors. */
+    private fun tryPatchAttributes(endpoint: String, entity: StringEntity): Boolean = try {
+        val resp = adminClient().makeRequest("PATCH", endpoint, emptyMap(), entity)
+        resp.restStatus().status in 200..299
+    } catch (e: ResponseException) {
+        // Treat common “route not usable / blocked” statuses as a soft failure (false), rethrow other errors.
+        val softStatuses = setOf(
+            RestStatus.NOT_FOUND, RestStatus.METHOD_NOT_ALLOWED, RestStatus.FORBIDDEN, RestStatus.UNAUTHORIZED, RestStatus.BAD_REQUEST,
+        )
+        if (e.response.restStatus() in softStatuses) false else throw e
+    } catch (_: Exception) {
+        // admin client couldn't reach security, treat as soft failure to try the next route
+        false
+    }
+
+    protected fun addAttributesToAdmin(attributes: Map<String, String>) {
+        val endpoints = listOf(
+            "/_plugins/_security/api/internalusers/admin",
+            "/_opendistro/_security/api/internalusers/admin",
+        )
+
+        val addBody = buildAttributesPatch("add", attributes)
+        val replaceBody = buildAttributesPatch("replace", attributes)
+
+        for (endpoint in endpoints) {
+            // First try ADD (creates /attributes if missing)
+            if (tryPatchAttributes(endpoint, addBody)) return
+            // Then try REPLACE (updates if it already exists)
+            if (tryPatchAttributes(endpoint, replaceBody)) return
+        }
+
+        logger.info("Could not set admin attributes via any Security route; continuing without attributes.")
+    }
+
     @Before
     protected fun disableIndexStateManagementJitter() {
         // jitter would add a test-breaking delay to the integration tests
diff --git a/src/test/resources/mappings/cached-opendistro-ism-config.json b/src/test/resources/mappings/cached-opendistro-ism-config.json
index 845bfe34c..68958f5e4 100644
--- a/src/test/resources/mappings/cached-opendistro-ism-config.json
+++ b/src/test/resources/mappings/cached-opendistro-ism-config.json
@@ -1,6 +1,6 @@
 {
   "_meta" : {
-    "schema_version": 24
+    "schema_version": 25
   },
   "dynamic": "strict",
   "properties": {
@@ -644,6 +644,10 @@
                   "type" : "keyword"
                 }
               }
+            },
+            "custom_attributes": {
+              "type": "object",
+              "dynamic": "true"
             }
           }
         }