Potential Privileged Escalation via SamAccountName Spoofing
editPotential Privileged Escalation via SamAccountName Spoofing
editIdentifies 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.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-system.*
- logs-windows.*
Severity: high
Risk score: 73
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
- https://support.microsoft.com/en-us/topic/kb5008102-active-directory-security-accounts-manager-hardening-changes-cve-2021-42278-5975b463-4c95-45e1-831a-d120004e258e
- https://cloudbrothers.info/en/exploit-kerberos-samaccountname-spoofing/
- https://github.com/cube0x0/noPac
- https://twitter.com/exploitph/status/1469157138928914432
- https://exploit.ph/cve-2021-42287-cve-2021-42278-weaponisation.html
Tags:
- 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
Version: 108
Rule authors:
- Elastic
Rule license: Elastic License v2
Setup
editSetup
If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
events will not define event.ingested and default fallback for EQL rules was not added until version 8.2.
Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
event.ingested to @timestamp.
For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
Rule query
editiam where event.action == "renamed-user-account" and /* machine account name renamed to user like account name */ winlog.event_data.OldTargetUserName : "*$" and not winlog.event_data.NewTargetUserName : "*$"
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Privilege Escalation
- ID: TA0004
- Reference URL: https://attack.mitre.org/tactics/TA0004/
-
Technique:
- Name: Exploitation for Privilege Escalation
- ID: T1068
- Reference URL: https://attack.mitre.org/techniques/T1068/
-
Technique:
- Name: Valid Accounts
- ID: T1078
- Reference URL: https://attack.mitre.org/techniques/T1078/
-
Sub-technique:
- Name: Domain Accounts
- ID: T1078.002
- Reference URL: https://attack.mitre.org/techniques/T1078/002/
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Account Manipulation
- ID: T1098
- Reference URL: https://attack.mitre.org/techniques/T1098/