def is_admin_policy(policy_doc):
# TODO Use find_admin.py code instead of copy pasting it here.
for stmt in make_list(policy_doc['Statement']):
if stmt['Effect'] == 'Allow':
actions = make_list(stmt.get('Action', []))
for action in actions:
if action == '*' or action == '*:*' or action == 'iam:*':
return True
return False
def is_admin_policy(policy_doc):
# TODO Use find_admin.py code instead of copy pasting it here.
for stmt in make_list(policy_doc["Statement"]):
if stmt["Effect"] == "Allow":
actions = make_list(stmt.get("Action", []))
for action in actions:
if action == "*" or action == "*:*" or action == "iam:*":
return True
return False
def is_admin_policy(
policy_doc, location, findings, region, privs_to_look_for, include_retricted
):
# This attempts to identify policies that directly allow admin privs, or indirectly through possible
# privilege escalation (ex. iam:PutRolePolicy to add an admin policy to itself).
# It is a best effort. It will have false negatives, meaning it may not identify an admin policy
# when it should, and may have false positives.
for stmt in make_list(policy_doc["Statement"]):
if stmt["Effect"] == "Allow":
# Check for use of NotAction, if they are allowing everything except a set, with no restrictions,
# this is bad.
not_actions = make_list(stmt.get("NotAction", []))
if (
not_actions != []
and stmt.get("Resource", "") == "*"
and stmt.get("Condition", "") == ""
):
if "iam:*" in not_actions:
# This is used for PowerUsers, where they can do everything except IAM actions
return False
findings.add(
Finding(
region,
"IAM_NOTACTION_ALLOW",
location,
resource_details={"Statement": stmt},
)
)
return True
actions = make_list(stmt.get("Action", []))
for action in actions:
if action == "*" or action == "*:*" or action == "iam:*":
if stmt.get("Resource", "") != "*":
findings.add(
Finding(
region,
"IAM_UNEXPECTED_FORMAT",
location,
resource_details={
"comment": "This policy is oddly allowing all actions, but is restricted to a specific resource. This is a confusing way of restricting access that may be more privileged than expected.",
"statement": stmt,
},
)
)
return True
# Look for privilege escalations
if action_matches(action, privs_to_look_for):
if include_retricted:
return True
elif (
stmt.get("Resource", "") == "*"
and stmt.get("Condition", "") == ""
):
return True
return False
def is_admin_policy(policy_doc, location):
# This attempts to identify policies that directly allow admin privs, or indirectly through possible
# privilege escalation (ex. iam:PutRolePolicy to add an admin policy to itself).
# It is a best effort. It will have false negatives, meaning it may not identify an admin policy
# when it should, and may have false positives.
for stmt in make_list(policy_doc['Statement']):
if stmt['Effect'] == 'Allow':
# Check for use of NotAction, if they are allowing everything except a set, with no restrictions,
# this is bad.
not_actions = make_list(stmt.get('NotAction', []))
if not_actions != [] and stmt.get(
'Resource', '') == '*' and stmt.get('Condition', '') == '':
if 'iam:*' in not_actions:
# This is used for PowerUsers, where they can do everything except IAM actions
return False
log_warning(
'Use of Allow and NotAction on Resource * is likely unwanted',
location, [stmt])
return True
actions = make_list(stmt.get('Action', []))
for action in actions:
if action == '*' or action == '*:*' or action == 'iam:*':
if stmt.get('Resource', '') != '*':
log_warning('Admin policy not using a Resource of *',
location, [stmt.get('Resource', '')])
return True
# Look for privilege escalations
if stmt.get('Resource', '') == '*' and stmt.get(
'Condition', ''
) == '' and (action_matches(
action,
[
'iam:PutRolePolicy',
'iam:AddUserToGroup',
'iam:AddRoleToInstanceProfile',
'iam:AttachGroupPolicy',
'iam:AttachRolePolicy',
'iam:AttachUserPolicy',
'iam:ChangePassword',
'iam:CreateAccessKey',
# Check for the rare possibility that an actor has a Deny policy on themselves,
# so they try to escalate privs by removing that policy
'iam:DeleteUserPolicy',
'iam:DetachGroupPolicy',
'iam:DetachRolePolicy',
'iam:DetachUserPolicy'
])):
return True
return False
def audit_iam(findings, region):
# By calling the code to find the admins, we'll exercise the code that finds problems.
find_admins_in_account(region, findings)
# By default we get the findings for the admins, but we can also look for specific
# privileges, so we'll look for who has s3:ListAllMyBuckets and then only use those
# findings that are for a compute resource having this privilege
s3_listing_findings = Findings()
s3_get_findings = Findings()
# TODO Running find_admins_in_account is really slow, and now we're running it 3 times.
# So figure out a way to run it once.
find_admins_in_account(region,
s3_listing_findings,
privs_to_look_for=["s3:ListAllMyBuckets"])
find_admins_in_account(region,
s3_get_findings,
privs_to_look_for=["s3:GetObject"])
for flist in s3_listing_findings:
if flist.issue_id != "IAM_UNEXPECTED_ADMIN_PRINCIPAL":
continue
services = make_list(
flist.resource_details.get("Principal", {}).get("Service", ""))
for service in services:
if service in [
"config.amazonaws.com",
"trustedadvisor.amazonaws.com",
"macie.amazonaws.com",
]:
continue
# If we are here then we have a principal that can list S3 buckets,
# and is associated with an unexpected service,
# so check if they can read data from them as well
for fget in s3_get_findings:
if (fget.issue_id == "IAM_UNEXPECTED_ADMIN_PRINCIPAL"
and fget.resource_id == flist.resource_id):
# If we are here, then the principal can list S3 buckets and get objects
# from them, and is not an unexpected service. Ensure we haven't already
# recorded this as an unexpected admin.
already_recorded = False
for f in findings:
if (f.resource_id == fget.resource_id and f.issue_id
== "IAM_UNEXPECTED_ADMIN_PRINCIPAL"):
already_recorded = True
break
if not already_recorded:
flist.issue_id = "IAM_UNEXPECTED_S3_EXFIL_PRINCIPAL"
findings.add(flist)
# Don't record this multiple times if multiple services are listed
break
def check_for_bad_policy(findings, region, arn, policy_text):
for statement in make_list(policy_text["Statement"]):
# Checking for signatures of the bad MFA policy from
# https://web.archive.org/web/20170602002425/https://docs.aws.amazon.com/IAM/latest/UserGuide/tutorial_users-self-manage-mfa-and-creds.html
# and
# https://github.com/awsdocs/iam-user-guide/blob/cfe14c674c494d07ba0ab952fe546fdd587da65d/doc_source/id_credentials_mfa_enable_virtual.md#permissions-required
if (
statement.get("Sid", "") == "AllowIndividualUserToManageTheirOwnMFA"
or statement.get("Sid", "")
== "AllowIndividualUserToViewAndManageTheirOwnMFA"
):
if "iam:DeactivateMFADevice" in make_list(statement.get("Action", [])):
findings.add(Finding(region, "IAM_BAD_MFA_POLICY", arn, policy_text))
return
elif (
statement.get("Sid", "")
== "BlockAnyAccessOtherThanAboveUnlessSignedInWithMFA"
):
if "iam:*" in make_list(statement.get("NotAction", [])):
findings.add(Finding(region, "IAM_BAD_MFA_POLICY", arn, policy_text))
return
def is_admin_policy(policy_doc, location, findings, region):
# This attempts to identify policies that directly allow admin privs, or indirectly through possible
# privilege escalation (ex. iam:PutRolePolicy to add an admin policy to itself).
# It is a best effort. It will have false negatives, meaning it may not identify an admin policy
# when it should, and may have false positives.
for stmt in make_list(policy_doc['Statement']):
if stmt['Effect'] == 'Allow':
# Check for use of NotAction, if they are allowing everything except a set, with no restrictions,
# this is bad.
not_actions = make_list(stmt.get('NotAction', []))
if not_actions != [] and stmt.get(
'Resource', '') == '*' and stmt.get('Condition', '') == '':
if 'iam:*' in not_actions:
# This is used for PowerUsers, where they can do everything except IAM actions
return False
findings.add(
Finding(region,
'IAM_NOTACTION_ALLOW',
location,
resource_details={'Statement': stmt}))
return True
actions = make_list(stmt.get('Action', []))
for action in actions:
if action == '*' or action == '*:*' or action == 'iam:*':
if stmt.get('Resource', '') != '*':
findings.add(
Finding(
region,
'IAM_UNEXPECTED_FORMAT',
location,
resource_details={
'comment':
'This policy is oddly allowing all actions, but is restricted to a specific resource. This is a confusing way of restricting access that may be more privileged than expected.',
'statement': stmt
}))
return True
# Look for privilege escalations
if stmt.get('Resource', '') == '*' and stmt.get(
'Condition', ''
) == '' and (action_matches(
action,
[
'iam:PutRolePolicy',
'iam:AddUserToGroup',
'iam:AddRoleToInstanceProfile',
'iam:AttachGroupPolicy',
'iam:AttachRolePolicy',
'iam:AttachUserPolicy',
'iam:ChangePassword',
'iam:CreateAccessKey',
# Check for the rare possibility that an actor has a Deny policy on themselves,
# so they try to escalate privs by removing that policy
'iam:DeleteUserPolicy',
'iam:DetachGroupPolicy',
'iam:DetachRolePolicy',
'iam:DetachUserPolicy'
])):
return True
return False
def is_admin_policy(policy_doc, location, findings, region):
# This attempts to identify policies that directly allow admin privs, or indirectly through possible
# privilege escalation (ex. iam:PutRolePolicy to add an admin policy to itself).
# It is a best effort. It will have false negatives, meaning it may not identify an admin policy
# when it should, and may have false positives.
for stmt in make_list(policy_doc["Statement"]):
if stmt["Effect"] == "Allow":
# Check for use of NotAction, if they are allowing everything except a set, with no restrictions,
# this is bad.
not_actions = make_list(stmt.get("NotAction", []))
if (
not_actions != []
and stmt.get("Resource", "") == "*"
and stmt.get("Condition", "") == ""
):
if "iam:*" in not_actions:
# This is used for PowerUsers, where they can do everything except IAM actions
return False
findings.add(
Finding(
region,
"IAM_NOTACTION_ALLOW",
location,
resource_details={"Statement": stmt},
)
)
return True
actions = make_list(stmt.get("Action", []))
for action in actions:
if action == "*" or action == "*:*" or action == "iam:*":
if stmt.get("Resource", "") != "*":
findings.add(
Finding(
region,
"IAM_UNEXPECTED_FORMAT",
location,
resource_details={
"comment": "This policy is oddly allowing all actions, but is restricted to a specific resource. This is a confusing way of restricting access that may be more privileged than expected.",
"statement": stmt,
},
)
)
return True
# Look for privilege escalations
if (
stmt.get("Resource", "") == "*"
and stmt.get("Condition", "") == ""
and (
action_matches(
action,
[
"iam:PutRolePolicy",
"iam:AddUserToGroup",
"iam:AddRoleToInstanceProfile",
"iam:AttachGroupPolicy",
"iam:AttachRolePolicy",
"iam:AttachUserPolicy",
"iam:ChangePassword",
"iam:CreateAccessKey",
# Check for the rare possibility that an actor has a Deny policy on themselves,
# so they try to escalate privs by removing that policy
"iam:DeleteUserPolicy",
"iam:DetachGroupPolicy",
"iam:DetachRolePolicy",
"iam:DetachUserPolicy",
],
)
)
):
return True
return False
def test_make_list(self):
assert_equal(["hello"], make_list("hello"))
assert_equal(["hello"], make_list(["hello"]))
