Potential Privileged Escalation via SamAccountName Spoofing

calendar Oct 15, 2024 · Domain: Endpoint OS: Windows Use Case: Threat Detection Tactic: Persistence Tactic: Privilege Escalation Use Case: Active Directory Monitoring Data Source: Active Directory Use Case: Vulnerability Data Source: System  ·
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Identifies a suspicious computer account name rename event, which may indicate an attempt to exploit CVE-2021-42278 to elevate privileges from a standard domain user to a user with domain admin privileges. CVE-2021-42278 is a security vulnerability that allows potential attackers to impersonate a domain controller via samAccountName attribute spoofing.

Elastic rule (View on GitHub)

 1[metadata]
 2creation_date = "2021/12/12"
 3integration = ["system", "windows"]
 4maturity = "production"
 5updated_date = "2024/10/15"
 6min_stack_version = "8.14.0"
 7min_stack_comments = "Breaking change at 8.14.0 for the Windows Integration."
 8
 9[rule]
10author = ["Elastic"]
11description = """
12Identifies a suspicious computer account name rename event, which may indicate an attempt to exploit CVE-2021-42278 to
13elevate privileges from a standard domain user to a user with domain admin privileges. CVE-2021-42278 is a security
14vulnerability that allows potential attackers to impersonate a domain controller via samAccountName attribute spoofing.
15"""
16from = "now-9m"
17index = ["winlogbeat-*", "logs-system.*", "logs-windows.*"]
18language = "eql"
19license = "Elastic License v2"
20name = "Potential Privileged Escalation via SamAccountName Spoofing"
21references = [
22    "https://support.microsoft.com/en-us/topic/kb5008102-active-directory-security-accounts-manager-hardening-changes-cve-2021-42278-5975b463-4c95-45e1-831a-d120004e258e",
23    "https://cloudbrothers.info/en/exploit-kerberos-samaccountname-spoofing/",
24    "https://github.com/cube0x0/noPac",
25    "https://twitter.com/exploitph/status/1469157138928914432",
26    "https://exploit.ph/cve-2021-42287-cve-2021-42278-weaponisation.html",
27]
28risk_score = 73
29rule_id = "bdcf646b-08d4-492c-870a-6c04e3700034"
30setup = """## Setup
31
32If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
33events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
34Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
35`event.ingested` to @timestamp.
36For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
37"""
38severity = "high"
39tags = [
40    "Domain: Endpoint",
41    "OS: Windows",
42    "Use Case: Threat Detection",
43    "Tactic: Persistence",
44    "Tactic: Privilege Escalation",
45    "Use Case: Active Directory Monitoring",
46    "Data Source: Active Directory",
47    "Use Case: Vulnerability",
48    "Data Source: System",
49]
50timestamp_override = "event.ingested"
51type = "eql"
52
53query = '''
54iam where event.action == "renamed-user-account" and
55  /* machine account name renamed to user like account name */
56  winlog.event_data.OldTargetUserName : "*$" and not winlog.event_data.NewTargetUserName : "*$"
57'''
58
59
60[[rule.threat]]
61framework = "MITRE ATT&CK"
62[[rule.threat.technique]]
63id = "T1068"
64name = "Exploitation for Privilege Escalation"
65reference = "https://attack.mitre.org/techniques/T1068/"
66
67[[rule.threat.technique]]
68id = "T1078"
69name = "Valid Accounts"
70reference = "https://attack.mitre.org/techniques/T1078/"
71[[rule.threat.technique.subtechnique]]
72id = "T1078.002"
73name = "Domain Accounts"
74reference = "https://attack.mitre.org/techniques/T1078/002/"
75
76
77
78[rule.threat.tactic]
79id = "TA0004"
80name = "Privilege Escalation"
81reference = "https://attack.mitre.org/tactics/TA0004/"
82[[rule.threat]]
83framework = "MITRE ATT&CK"
84[[rule.threat.technique]]
85id = "T1098"
86name = "Account Manipulation"
87reference = "https://attack.mitre.org/techniques/T1098/"
88
89
90[rule.threat.tactic]
91id = "TA0003"
92name = "Persistence"
93reference = "https://attack.mitre.org/tactics/TA0003/"

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