Match receiver indicators by package ID (#836)

src/mvt/android/modules/bugreport/dumpsys_receivers.py

@@ -35,24 +35,6 @@ class DumpsysReceivers(DumpsysReceiversArtifact, BugReportModule):
 
         self.results = results if results else {}
 
-    def check_indicators(self) -> None:
-        for result in self.results:
-            if self.indicators:
-                receiver_name = self.results[result][0]["receiver"]
-
-                # return IoC if the stix2 process name a substring of the receiver name
-                ioc_match = self.indicators.check_receiver_prefix(receiver_name)
-                if ioc_match:
-                    self.alertstore.critical(
-                        ioc_match.message,
-                        "",
-                        self.results[result][0],
-                        matched_indicator=ioc_match.ioc,
-                    )
-                    continue
-
-
-
     def run(self) -> None:
         content = self._get_dumpstate_file()
         if not content:

src/mvt/common/indicators.py

@@ -727,29 +727,6 @@ class Indicators:
 
         return None
 
-    def check_receiver_prefix(
-        self, receiver_name: str
-    ) -> Optional[IndicatorMatch]:
-        """Check the provided receiver name against the list of indicators.
-        An IoC match is detected when a substring of the receiver matches the indicator.
-
-        :param receiver_name: Receiver name to check against app ID indicators
-        :type receiver_name: str
-        :returns: IndicatorMatch if matched, otherwise None
-
-        """
-        if not receiver_name:
-            return None
-
-        for ioc in self.get_iocs("app_ids"):
-            if ioc.value.lower() in receiver_name.lower():
-                return IndicatorMatch(
-                    ioc=ioc,
-                    message=f'Found a known suspicious receiver with name "{receiver_name}" matching indicators from "{ioc.name}"',
-                )
-
-        return None
-
     def check_android_property_name(
         self, property_name: str
     ) -> Optional[IndicatorMatch]:

tests/android_bugreport/test_bugreport.py

@@ -9,6 +9,7 @@ from pathlib import Path
 from mvt.android.modules.bugreport.dumpsys_appops import DumpsysAppops
 from mvt.android.modules.bugreport.dumpsys_getprop import DumpsysGetProp
 from mvt.android.modules.bugreport.dumpsys_packages import DumpsysPackages
+from mvt.android.modules.bugreport.dumpsys_receivers import DumpsysReceivers
 from mvt.android.modules.bugreport.tombstones import Tombstones
 from mvt.common.module import run_module
 
@@ -60,6 +61,31 @@ class TestBugreportAnalysis:
         m = self.launch_bug_report_module(DumpsysGetProp)
         assert len(m.results) == 0
 
+    def test_receivers_match_exact_package_name(self, indicators_factory):
+        intent = "android.intent.action.PHONE_STATE"
+        false_positive = {
+            "package_name": "com.android.phone",
+            "receiver": (
+                "com.android.phone/"
+                "com.android.services.telephony.sip.SipIncomingCallReceiver"
+            ),
+        }
+        malicious_receiver = {
+            "package_name": "com.android.services",
+            "receiver": "com.android.services/com.example.SomeReceiver",
+        }
+        module = DumpsysReceivers(
+            results={intent: [false_positive, malicious_receiver]}
+        )
+        module.indicators = indicators_factory(app_ids=["com.android.services"])
+
+        module.check_indicators()
+
+        assert len(module.alertstore.alerts) == 1
+        alert = module.alertstore.alerts[0]
+        assert alert.event == {intent: malicious_receiver}
+        assert alert.matched_indicator.value == "com.android.services"
+
     def test_tombstones_modules(self):
         m = self.launch_bug_report_module(Tombstones)
         assert len(m.results) == 2