Fix accessibility service alerts

src/mvt/android/artifacts/dumpsys_accessibility.py

@@ -10,16 +10,20 @@ from .artifact import AndroidArtifact
 
 class DumpsysAccessibilityArtifact(AndroidArtifact):
     def check_indicators(self) -> None:
-        if not self.indicators:
-            return
-
         for result in self.results:
-            ioc_match = self.indicators.check_app_id(result["package_name"])
-            if ioc_match:
-                self.alertstore.critical(
-                    ioc_match.message, "", result, matched_indicator=ioc_match.ioc
+            if self.indicators:
+                ioc_match = self.indicators.check_app_id(result["package_name"])
+                if ioc_match:
+                    self.alertstore.critical(
+                        ioc_match.message, "", result, matched_indicator=ioc_match.ioc
+                    )
+                    continue
+
+            self.alertstore.medium(
+                f'Found accessibility service: "{result["service"]}"',
+                "",
+                result,
                 )
-                continue
 
     def parse(self, content: str) -> None:
         """

src/mvt/common/alerts.py

@@ -219,7 +219,7 @@ class AlertStore:
         return alerts
 
     def save_timeline(self, timeline_path: str) -> None:
-        with open(timeline_path, "a+", encoding="utf-8") as handle:
+        with open(timeline_path, "w", encoding="utf-8") as handle:
             csvoutput = csv.writer(
                 handle,
                 delimiter=",",

src/mvt/common/module.py

@@ -259,7 +259,7 @@ def save_timeline(timeline: list, timeline_path: str, is_utc: bool = True) -> No
     :param timeline_path: Path to the csv file to store the timeline to
 
     """
-    with open(timeline_path, "a+", encoding="utf-8") as handle:
+    with open(timeline_path, "w", encoding="utf-8") as handle:
         csvoutput = csv.writer(
             handle, delimiter=",", quotechar='"', quoting=csv.QUOTE_ALL, escapechar="\\"
         )

tests/android/test_artifact_dumpsys_accessibility.py

@@ -5,6 +5,7 @@
 import logging
 
 from mvt.android.artifacts.dumpsys_accessibility import DumpsysAccessibilityArtifact
+from mvt.common.alerts import AlertLevel
 from mvt.common.indicators import Indicators
 
 from ..utils import get_artifact
@@ -38,6 +39,19 @@ class TestDumpsysAccessibilityArtifact:
         assert da.results[0]["package_name"] == "com.malware.accessibility"
         assert da.results[0]["service"] == "com.malware.service.malwareservice"
 
+    def test_accessibility_service_alert(self):
+        da = DumpsysAccessibilityArtifact()
+        file = get_artifact("android_data/dumpsys_accessibility_v14_or_later.txt")
+        with open(file) as f:
+            data = f.read()
+        da.parse(data)
+
+        da.check_indicators()
+
+        assert len(da.alertstore.alerts) == 1
+        assert da.alertstore.alerts[0].level == AlertLevel.MEDIUM
+        assert da.alertstore.alerts[0].event == da.results[0]
+
     def test_ioc_check(self, indicator_file):
         da = DumpsysAccessibilityArtifact()
         file = get_artifact("android_data/dumpsys_accessibility.txt")
@@ -51,4 +65,12 @@ class TestDumpsysAccessibilityArtifact:
         da.indicators = ind
         assert len(da.alertstore.alerts) == 0
         da.check_indicators()
-        assert len(da.alertstore.alerts) == 1
+        assert len(da.alertstore.alerts) == len(da.results)
+        assert da.alertstore.count(AlertLevel.MEDIUM) == 3
+        assert da.alertstore.count(AlertLevel.CRITICAL) == 1
+        critical_alert = next(
+            alert
+            for alert in da.alertstore.alerts
+            if alert.level == AlertLevel.CRITICAL
+        )
+        assert critical_alert.event["package_name"] == "com.sec.android.app.camera"