Merge pull request #58 from trussworks/expire-inactive-accounts

Expire inactive accounts

Author: sheenamt

README.md

@@ -12,7 +12,9 @@ An auditing tool for AWS keys that audits, alerts, and disable keys if not withi
 
 Sleuth runs periodically, normally once a day in the middle of business hours. Sleuth does the following:
 
-- Inspect each Access Key based on set age threshold (default 90 days)
+- Inspect each Access Key based on:
+  - set creation age threshold (default 90 days)
+  - set last accessed age threshold (optional, set to creation age threshold as default)
 - If Access Key is approaching threshold will ping user with a reminder to cycle key
 - If key age is at or over threshold will disable Access Key along with a final notice
 
@@ -81,6 +83,7 @@ module "iam_sleuth" {
     ENABLE_AUTO_EXPIRE  = "false"
     EXPIRATION_AGE      = 90
     WARNING_AGE         = 50
+    LAST_USED_AGE       = 30
     SLACK_URL           = data.aws_ssm_parameter.slack_url.value
     SNS_TOPIC           = ""
     MSG_TITLE           = "Key Rotation Instructions"
@@ -101,8 +104,9 @@ The behavior can be configured by environment variables.
 | Name | Description |
 |------|------------ |
 | ENABLE_AUTO_EXPIRE | Must be set to `true` for key disable action |
-| EXPIRATION_AGE | Age in days to disable a AWS key |
-| WARNING_AGE | Age in days of key to send notifications, must be lower than EXPIRATION_AGE |
+| EXPIRATION_AGE | Age of key creation (in days) to disable a AWS key |
+| WARNING_AGE | Age of key creation (in days) to send notifications, must be lower than EXPIRATION_AGE |
+| LAST_USED_AGE | OPTIONAL, defaults to EXPIRATION_AGE, Age of last key usage (in days) to send notifications, must be lower than or equal to EXPIRATION_AGE |
 | MSG_TITLE | Title of the notification message |
 | MSG_TEXT | Instructions on key rotation |
 | SLACK_URL | Incoming webhook to send notifications to |

examples/simple/main.tf

@@ -29,6 +29,7 @@ module "iam_sleuth" {
     ENABLE_AUTO_EXPIRE  = false
     EXPIRATION_AGE      = 90
     WARNING_AGE         = 85
+    LAST_USED_AGE       = 30
     MSG_TITLE           = "Key Rotation Instructions"
     MSG_TEXT            = "Please run key rotation tool!"
   }

sleuth/sleuth/auditor.py

@@ -16,47 +16,57 @@ class Key():
     key_id = ""
     created = None
     status = ""
+    last_used = None
     audit_state = None
 
-    age = 0
+    creation_age = 0
+    access_age = 0
     valid_for = 0
 
-    def __init__(self, username, key_id, status, created):
+    def __init__(self, username, key_id, status, created, last_used):
         self.username = username
         self.key_id = key_id
         self.status = status
         self.created = created
+        self.last_used = last_used
 
-        self.age = (dt.datetime.now(dt.timezone.utc) - self.created).days
+        self.creation_age = (dt.datetime.now(dt.timezone.utc) - self.created).days
+        self.access_age = (dt.datetime.now(dt.timezone.utc) - self.last_used).days
 
-    def audit(self, rotate_age, expire_age):
+    def audit(self, rotate_age, expire_age, max_last_used_age):
         """
-        Audits the key and sets the status state based on key age
+        Audits the key and sets the status state based on key creation age and last used age
 
-        Note if the key is below rotate the audit_state=good. If the key is disabled will be marked as disabled.
+        Note if the key is below rotate or last used age, the audit_state=good.
+        If the key is disabled will be marked as disabled.
 
         Parameters:
         rotate (int): Age key must be before audit_state=old
         expire (int): Age key must be before audit_state=expire
+        last_used_age (int): Age of last key usage must be before audit_state=expire
 
         Returns:
         None
         """
         assert(rotate_age < expire_age)
+        assert(max_last_used_age <= expire_age)
 
         # set the valid_for in the object
-        self.valid_for = expire_age - self.age
+        self.valid_for = expire_age - self.creation_age
 
         # lets audit the age
-        if self.age < rotate_age:
-            self.audit_state = 'good'
-        if self.age >= rotate_age and self.age < expire_age:
-            self.audit_state = 'old'
-        if self.age >= expire_age:
+        if self.creation_age >= expire_age:
             self.audit_state = 'expire'
-        if self.status == 'Inactive' and os.environ['ENABLE_AUTO_EXPIRE'] == 'true':
-            self.audit_state = 'disabled'
+        elif self.access_age >= max_last_used_age:
+            self.audit_state = 'expire'
+        elif self.creation_age >= rotate_age and self.creation_age < expire_age:
+            self.audit_state = 'old'
+        elif self.creation_age < rotate_age:
+            self.audit_state = 'good'
 
+        # lets audit the status
+        if self.status == 'Inactive' and os.environ.get('ENABLE_AUTO_EXPIRE', False) == 'true':
+            self.audit_state = 'disabled'
 
 class User():
     username = ""
@@ -69,9 +79,9 @@ def __init__(self, user_id, username, slack_id=None):
         self.username = username
         self.slack_id = slack_id
 
-    def audit(self, rotate=80, expire=90):
+    def audit(self, rotate=80, expire=90, last_used=90):
         for k in self.keys:
-            k.audit(rotate, expire)
+            k.audit(rotate, expire, last_used)
 
 def print_key_report(users):
     """Prints table of report
@@ -92,18 +102,20 @@ def print_key_report(users):
                 u.slack_id,
                 k.key_id,
                 k.audit_state,
-                k.age
+                k.creation_age,
+                k.access_age
             ])
 
-    print(tabulate(tbl_data, headers=['UserName', 'Slack ID', 'Key ID', 'Status', 'Age in Days']))
+    print(tabulate(tbl_data, headers=['UserName', 'Slack ID', 'Key ID', 'Status', 'Age in Days', 'Last Access Age']))
 
 
 def audit():
     iam_users = get_iam_users()
 
     # lets audit keys so the ages and state are set
     for u in iam_users:
-        u.audit(int(os.environ['WARNING_AGE']), int(os.environ['EXPIRATION_AGE']))
+        # Do not require last used age, set to expiration age as default
+        u.audit(int(os.environ['WARNING_AGE']), int(os.environ['EXPIRATION_AGE']), int(os.environ.get('LAST_USED_AGE', os.environ['EXPIRATION_AGE'])))
 
     if os.environ.get('DEBUG', False):
         print_key_report(iam_users)

sleuth/sleuth/services.py

@@ -25,13 +25,16 @@ def get_iam_key_info(user):
     list (Key): Return list of keys for a single user
     """
     from sleuth.auditor import Key
-    resp = IAM.list_access_keys(UserName=user.username)
     keys = []
-    for k in resp['AccessKeyMetadata']:
+    key_info = IAM.list_access_keys(UserName=user.username)
+    for k in key_info['AccessKeyMetadata']:
+        access_date=IAM.get_access_key_last_used(AccessKeyId=k['AccessKeyId'])
         keys.append(Key(k['UserName'],
                         k['AccessKeyId'],
                         k['Status'],
-                        k['CreateDate']))
+                        k['CreateDate'],
+                        access_date['AccessKeyLastUsed']['LastUsedDate'] if 'LastUsedDate' in access_date['AccessKeyLastUsed'] else k['CreateDate']))
+
     return keys
 
 

sleuth/tests/test_auditor.py

@@ -5,59 +5,69 @@
 
 from sleuth.auditor import Key
 
-
 @freeze_time("2019-01-16")
 class TestKey():
     def test_normal(self):
         """Normal happy path, key is good"""
         created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
-        k = Key('username', 'keyid', 'Active', created)
-        k.audit(60, 80)
-
-        assert k.age == 15
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        k = Key('username', 'keyid', 'Active', created, last_used)
+        k.audit(60, 80, 20)
+        assert k.creation_age == 15
         assert k.audit_state == 'good'
 
     def test_rotate(self):
         """Key is past rotate age, key is marked as old"""
         created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
-        k = Key('username', 'keyid', 'Active', created)
-        k.audit(10, 80)
-
-        assert k.audit_state == 'old'
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        key = Key('username', 'keyid', 'Active', created, last_used)
+        key.audit(10, 80, 20)
+        assert key.audit_state == 'old'
 
     def test_old(self):
         """Key is past max threshold, key is marked as expired"""
         created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
-        k = Key('username', 'keyid', 'Active', created)
-        k.audit(10, 11)
-
-        assert k.audit_state == 'expire'
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        key = Key('username', 'keyid', 'Active', created, last_used)
+        key.audit(10, 11, 10)
+        assert key.audit_state == 'expire'
 
     def test_no_disable(self, monkeypatch):
         """Key is disabled AWS status of Inactive, but disabling is turned off so key remains audit state expire"""
         monkeypatch.setenv('ENABLE_AUTO_EXPIRE', 'false')
         created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
-        k = Key('username', 'keyid', 'Inactive', created)
-
-        k.audit(10, 11)
-        assert k.audit_state == 'expire'
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        key = Key('user2', 'ldasfkk', 'Inactive', created, last_used)
+        key.audit(10, 11, 10)
+        assert key.audit_state == 'expire'
 
-    def test_inactive(self, monkeypatch):
+    def test_last_used(self, monkeypatch):
+        """Key has not been used in X days, key marked is disabled"""
+        monkeypatch.setenv('ENABLE_AUTO_EXPIRE', 'true')
+        monkeypatch.setenv('LAST_USED_AGE', '10')
+        created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        key = Key('user3', 'kljin', 'Active', created, last_used)
+        key.audit(10, 11, 1)
+        assert key.audit_state == 'expire'
+        key.audit(60, 80, 1)
+        assert key.audit_state == 'expire'
+
+    def test_disabled(self, monkeypatch):
         """Key is disabled AWS status of Inactive, key marked is disabled"""
         monkeypatch.setenv('ENABLE_AUTO_EXPIRE', 'true')
         created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
-        k = Key('username', 'keyid', 'Inactive', created)
-
-        k.audit(10, 11)
-        assert k.audit_state == 'disabled'
-        k.audit(60, 80)
-        assert k.audit_state == 'disabled'
-
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        key = Key('user2', 'ldasfkk', 'Inactive', created, last_used)
+        key.audit(10, 11, 10)
+        assert key.audit_state == 'disabled'
+        key.audit(60, 80, 30)
+        assert key.audit_state == 'disabled'
 
     def test_invalid(self):
         """Key is disabled AWS status of Inactive, key marked is disabled"""
         created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
-        k = Key('username', 'keyid', 'Inactive', created)
-
+        last_used = datetime.datetime(2019, 1, 2, tzinfo=datetime.timezone.utc)
+        key = Key('user2', 'ldasfkk', 'Inactive', created, last_used)
         with pytest.raises(AssertionError):
-            k.audit(5, 1)
+            key.audit(5, 1, 1)

sleuth/tests/test_services.py

@@ -7,11 +7,12 @@
 from sleuth.auditor import Key, User
 
 created = datetime.datetime(2019, 1, 1, tzinfo=datetime.timezone.utc)
+lastused = created = datetime.datetime(2019, 1, 3, tzinfo=datetime.timezone.utc)
 user1 = User('user1', 'slackuser1', 'U12345')
 user2 = User('user1', 'slackuser1', 'U67890')
-key1 = Key('user1', 'asdfksakfa', 'Active', created)
+key1 = Key('user1', 'asdfksakfa', 'Active', created, lastused)
 key1.audit_state = 'old'
-key2 = Key('user2', 'ldasfkk', 'Active', created)
+key2 = Key('user2', 'ldasfkk', 'Active', created, lastused)
 key2.audit_state = 'expire'
 user1.keys = [key1]
 user2.keys = [key2]