feat(api): finding group first_seen_at semantics and resource delta (#10595)

api/CHANGELOG.md

@@ -28,6 +28,7 @@ All notable changes to the **Prowler API** are documented in this file.
 - Membership `post_delete` signal using raw FK ids to avoid `DoesNotExist` during cascade deletions [(#10497)](https://github.com/prowler-cloud/prowler/pull/10497)
 - Finding group resources endpoints returning false 404 when filters match no results, and `sort` parameter being ignored [(#10510)](https://github.com/prowler-cloud/prowler/pull/10510)
 - Jira integration failing with `JiraInvalidIssueTypeError` on non-English Jira instances due to hardcoded `"Task"` issue type; now dynamically fetches available issue types per project [(#10534)](https://github.com/prowler-cloud/prowler/pull/10534)
+- Finding group `first_seen_at` now reflects when a new finding appeared in the scan instead of the oldest carry-forward date across all unchanged findings [(#10595)](https://github.com/prowler-cloud/prowler/pull/10595)
 - Attack Paths: Remove `clear_cache` call from read-only query endpoints; cache clearing belongs to the scan/ingestion flow, not API queries [(#10586)](https://github.com/prowler-cloud/prowler/pull/10586)
 
 ### 🔐 Security

api/src/backend/api/v1/serializers.py

@@ -4216,6 +4216,7 @@ class FindingGroupResourceSerializer(BaseSerializerV1):
     provider = serializers.SerializerMethodField()
     status = serializers.CharField()
     severity = serializers.CharField()
+    delta = serializers.CharField(required=False, allow_null=True)
     first_seen_at = serializers.DateTimeField(required=False, allow_null=True)
     last_seen_at = serializers.DateTimeField(required=False, allow_null=True)
     muted_reason = serializers.CharField(required=False, allow_null=True)

api/src/backend/api/v1/views.py

@@ -7234,6 +7234,7 @@ class FindingGroupViewSet(BaseRLSViewSet):
     _RESOURCE_SORT_MAP = {
         "status": "status_order",
         "severity": "severity_order",
+        "delta": "delta_order",
         "first_seen_at": "first_seen_at",
         "last_seen_at": "last_seen_at",
         "resource.uid": "resource_uid",
@@ -7370,6 +7371,22 @@ class FindingGroupViewSet(BaseRLSViewSet):
                         output_field=IntegerField(),
                     )
                 ),
+                delta_order=Max(
+                    Case(
+                        When(
+                            finding__delta="new",
+                            finding__muted=False,
+                            then=Value(2),
+                        ),
+                        When(
+                            finding__delta="changed",
+                            finding__muted=False,
+                            then=Value(1),
+                        ),
+                        default=Value(0),
+                        output_field=IntegerField(),
+                    )
+                ),
                 first_seen_at=Min("finding__first_seen_at"),
                 last_seen_at=Max("finding__inserted_at"),
                 # Max() on muted_reason / check_metadata is safe because
@@ -7402,6 +7419,22 @@ class FindingGroupViewSet(BaseRLSViewSet):
                 output_field=IntegerField(),
             )
         ),
+        "delta_order": lambda: Max(
+            Case(
+                When(
+                    finding__delta="new",
+                    finding__muted=False,
+                    then=Value(2),
+                ),
+                When(
+                    finding__delta="changed",
+                    finding__muted=False,
+                    then=Value(1),
+                ),
+                default=Value(0),
+                output_field=IntegerField(),
+            )
+        ),
         "first_seen_at": lambda: Min("finding__first_seen_at"),
         "last_seen_at": lambda: Max("finding__inserted_at"),
         "resource_uid": lambda: Max("resource__uid"),
@@ -7448,6 +7481,14 @@ class FindingGroupViewSet(BaseRLSViewSet):
             else:
                 status = "MUTED"
 
+            delta_order = row.get("delta_order", 0)
+            if delta_order == 2:
+                delta = "new"
+            elif delta_order == 1:
+                delta = "changed"
+            else:
+                delta = None
+
             results.append(
                 {
                     "resource_id": row["resource_id"],
@@ -7463,6 +7504,7 @@ class FindingGroupViewSet(BaseRLSViewSet):
                     "severity": SEVERITY_ORDER_REVERSE.get(
                         severity_order, "informational"
                     ),
+                    "delta": delta,
                     "first_seen_at": row["first_seen_at"],
                     "last_seen_at": row["last_seen_at"],
                     "muted_reason": row.get("muted_reason"),

api/src/backend/tasks/jobs/scan.py

@@ -1824,7 +1824,9 @@ def aggregate_finding_group_summaries(tenant_id: str, scan_id: str):
                     filter=Q(status="FAIL", muted=False),
                 ),
                 # Use prefixed names to avoid conflict with model field names
-                agg_first_seen_at=Min("first_seen_at"),
+                agg_first_seen_at=Min(
+                    "first_seen_at", filter=Q(delta="new", muted=False)
+                ),
                 agg_last_seen_at=Max("inserted_at"),
                 agg_failing_since=Min(
                     "first_seen_at", filter=Q(status="FAIL", muted=False)