[rules] Add community rule to detect ssh login activity based on osqu…

…ery events (#1127)

* [rules] Add community rule to alert on ssh login activity based on osquery detection

* address comments

rules/community/guardduty/guard_duty_all.py

@@ -1,9 +1,9 @@
 """Alert on GuardDuty"""
-from rules.matchers import matchers
+from rules.matchers.matchers import GuardDutyMatcher
 from streamalert.shared.rule import rule
 
 
-@rule(logs=['cloudwatch:events'], matchers=[matchers.guard_duty])
+@rule(logs=['cloudwatch:events'], matchers=[GuardDutyMatcher.guard_duty])
 def guard_duty_all(*_):
     """
     author:         spiper

rules/community/osquery/ssh_login_activity.py

@@ -0,0 +1,19 @@
+"""Detect ssh login activity based on osquery last table"""
+from rules.matchers.matchers import OsqueryMatcher
+from streamalert.shared.rule import rule
+
+
+@rule(logs=['osquery:differential'],
+      matchers=[OsqueryMatcher.added, OsqueryMatcher.user_login])
+def ssh_login_activity(_):
+    """
+    author:           chunyong-lin
+    description:      Detect on ssh login activity to the linux host based on osquery
+                      last table. This rule assumes we use default osquery pack
+                      shipped with osquery package located at
+                      /usr/share/osquery/packs/incident-response.conf on the linux
+                      host. Update the pack name in rules/matchers/matchers.py if different.
+    reference:        https://osquery.io/schema/4.1.2#last
+    """
+
+    return True

rules/matchers/matchers.py

@@ -14,7 +14,40 @@
 @rule('root_logins', logs=['osquery:differential'],
       matchers=[matchers.prod, matchers.pci], outputs=['pagerduty:sample-integration'])
 """
+class GuardDutyMatcher:
+    """A class contains matchers for AWS GuardDuty service"""
 
+    @classmethod
+    def guard_duty(cls, rec):
+        return rec['detail-type'] == 'GuardDuty Finding'
 
-def guard_duty(record):
-    return record['detail-type'] == 'GuardDuty Finding'
+class OsqueryMatcher:
+    """A class defines contains matchers for Osquery events"""
+
+    _EVENT_TYPE_LOGIN = 7
+    _RUNLEVELS = {
+        '',
+        'LOGIN',
+        'reboot',
+        'shutdown',
+        'runlevel'
+    }
+
+
+    @classmethod
+    def added(cls, rec):
+        return rec['action'] == 'added'
+
+
+    @classmethod
+    def user_login(cls, rec):
+        """Capture user logins from the osquery last table
+        This matcher assumes we use default osquery pack shipped with osquery package
+        located at /usr/share/osquery/packs/incident-response.conf on the linux host.
+        Update the pack name (rec['name']) if it is different.
+        """
+        return (
+            rec['name'] == 'pack_incident-response_last' and
+            int(rec['columns']['type']) == cls._EVENT_TYPE_LOGIN and
+            (rec['columns']['username'] not in cls._RUNLEVELS)
+        )

tests/integration/rules/osquery/ssh_login_activity.json

@@ -0,0 +1,88 @@
+[
+  {
+    "data": {
+      "action": "added",
+      "calendarTime": "Wed Feb 12 21:38:11 2020 UTC",
+      "columns": {
+        "host": "10.0.2.2",
+        "pid": 12345,
+        "time": 1581542540,
+        "tty": "ttys001",
+        "type": "7",
+        "username": "vagrant"
+      },
+      "decorations": {
+        "envIdentifier": "fake-environment",
+        "roleIdentifier": "fake-role"
+      },
+      "epoch": "0",
+      "hostIdentifier": "...",
+      "log_type": "result",
+      "name": "pack_incident-response_last",
+      "unixTime": "1581543491"
+    },
+    "description": "This rule alerts on ssh logins to a linux host",
+    "log": "osquery:differential",
+    "service": "kinesis",
+    "source": "prefix_cluster1_streamalert",
+    "trigger_rules": [
+      "ssh_login_activity"
+    ]
+  },
+  {
+    "data": {
+      "action": "added",
+      "calendarTime": "Wed Feb 12 21:38:11 2020 UTC",
+      "columns": {
+        "host": "10.0.2.2",
+        "pid": 12345,
+        "time": 1581542540,
+        "tty": "ttys001",
+        "type": "7",
+        "username": "runlevel"
+      },
+      "decorations": {
+        "envIdentifier": "fake-environment",
+        "roleIdentifier": "fake-role"
+      },
+      "epoch": "0",
+      "hostIdentifier": "...",
+      "log_type": "result",
+      "name": "pack_incident-response_last",
+      "unixTime": "1581543491"
+    },
+    "description": "This rule will not alert on runlevel ssh logins",
+    "log": "osquery:differential",
+    "service": "kinesis",
+    "source": "prefix_cluster1_streamalert",
+    "trigger_rules": []
+  },
+  {
+    "data": {
+      "action": "added",
+      "calendarTime": "Wed Feb 12 21:38:11 2020 UTC",
+      "columns": {
+        "host": "10.0.2.2",
+        "pid": 12345,
+        "time": 1581542540,
+        "tty": "ttys001",
+        "type": "8",
+        "username": "runlevel"
+      },
+      "decorations": {
+        "envIdentifier": "fake-environment",
+        "roleIdentifier": "fake-role"
+      },
+      "epoch": "0",
+      "hostIdentifier": "...",
+      "log_type": "result",
+      "name": "pack_incident-response_last",
+      "unixTime": "1581543491"
+    },
+    "description": "This rule will not alert on ssh logout(type: 8)",
+    "log": "osquery:differential",
+    "service": "kinesis",
+    "source": "prefix_cluster1_streamalert",
+    "trigger_rules": []
+  }
+]