First Time AWS Cloudformation Stack Creation by User

calendar Nov 7, 2024 · Domain: Cloud Data Source: AWS Data Source: Amazon Web Services Data Source: Cloudformation Use Case: Asset Visibility Tactic: Execution  ·
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This rule detects the first time a principal calls AWS Cloudwatch CreateStack or CreateStackSet API. Cloudformation is used to create a single collection of cloud resources called a stack, via a defined template file. An attacker with the appropriate privileges could leverage Cloudformation to create specific resources needed to further exploit the environment. This is a new terms rule that looks for the first instance of this behavior in the last 10 days for a role or IAM user within a particular account.

Elastic rule (View on GitHub)

 1[metadata]
 2creation_date = "2020/07/25"
 3integration = ["aws"]
 4maturity = "production"
 5updated_date = "2024/11/07"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10This rule detects the first time a principal calls AWS Cloudwatch `CreateStack` or `CreateStackSet` API. Cloudformation
11is used to create a single collection of cloud resources called a stack, via a defined template file. An attacker with
12the appropriate privileges could leverage Cloudformation to create specific resources needed to further exploit the
13environment. This is a new terms rule that looks for the first instance of this behavior in the last 10 days for a role
14or IAM user within a particular account.
15"""
16false_positives = [
17    """
18    Verify whether the user identity should be using the `CreateStack` or `CreateStackSet` APIs. If known behavior is
19    causing false positives, it can be exempted from the rule. The "history_window_start" value can be modified to
20    reflect the expected frequency of known activity within a particular environment.
21    """,
22]
23from = "now-6m"
24index = ["filebeat-*", "logs-aws.cloudtrail-*"]
25language = "kuery"
26license = "Elastic License v2"
27name = "First Time AWS Cloudformation Stack Creation by User"
28references = [
29    "https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-cli-creating-stack.html/",
30    "https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/stacksets-concepts.html/",
31    "https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_CreateStack.html/",
32    "https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_CreateStackSet.html/",
33]
34risk_score = 47
35rule_id = "0415258b-a7b2-48a6-891a-3367cd9d4d31"
36severity = "medium"
37tags = [
38    "Domain: Cloud",
39    "Data Source: AWS",
40    "Data Source: Amazon Web Services",
41    "Data Source: Cloudformation",
42    "Use Case: Asset Visibility",
43    "Tactic: Execution",
44]
45timestamp_override = "event.ingested"
46type = "new_terms"
47
48query = '''
49event.dataset:aws.cloudtrail and event.provider:cloudformation.amazonaws.com and
50    event.action: (CreateStack or CreateStackSet) and event.outcome:success
51'''
52
53
54[[rule.threat]]
55framework = "MITRE ATT&CK"
56
57[rule.threat.tactic]
58id = "TA0002"
59name = "Execution"
60reference = "https://attack.mitre.org/tactics/TA0002/"
61
62[rule.new_terms]
63field = "new_terms_fields"
64value = ["cloud.account.id", "user.name"]
65[[rule.new_terms.history_window_start]]
66field = "history_window_start"
67value = "now-10d"

References

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