Query: write Sigma for Detect suspicious Kerberos TGT requests. Once an attacer obtains a computer certificate by abusing Active Directory Cert
Matching passage: Sigma rule: Detect suspicious Kerberos TGT requests. Once an attacer obtains a computer certificate by abusing Active Directory Cert. Logsource: windows / security. Rule: title: PetitPotam Suspicious Kerberos TGT Request id: 6a53d871-682d-40b6-83e0-b7c1a6c4e3a5 status: test description: 'Detect suspicious Kerberos TGT requests. Once an attacer obtains a computer certificate by abusing Active Directory Certificate Services in combination with PetitPotam, the next step would be to leverage the certificate for malicious purposes. One way of doing this is to request a Kerberos Ticket Granting Ticket using a tool like Rubeus. This request will generate a 4768 event with some unusual fields depending on the environment. This analytic will require tuning, we recommend filtering Account_Name to the Domain Controller computer accounts. ' references: - https://github.com/topotam/PetitPotam - https://isc.sans.edu/forums/diary/Active+Directory+Certificate+Services+ADCS+PKI+domain+admin+vulnerability/27668/ - https://github.com/splunk/security_content/blob/88d689fe8a055d8284337b9fad5d9152b42043db/detections/endpoint/petitpotam_suspicious_kerberos_tgt_request.yml author: Mauricio Velazco, Michael Haag date: 2021-09-02 modified: 2022-10-05 tags: - attack.credential-access - attack.t1187 logsource: product: windows service: security definition: The advanced audit policy setting "Account Logon > Kerberos Authentication Service" must be configured for Success/Failure detection: selection: EventID: 4768 TargetUserName|endswith: $ CertThumbprint|contains: '*' filter_local: IpAddress: ::1 filter_thumbprint: CertThumbprint: '' condition: selection and not 1 of filter_* falsepositives: - False positives are possible if the environment is using certificates for authentication. We recommend filtering Account_Name to the Domain Controller computer accounts. level: high
Near-miss passage: Sigma rule: Detects the usage of the "Squirrel.exe" to download arbitrary files. This binary is part of multiple Electron based soft. Logsource: windows / process_creation. Rule: title: Arbitrary File Download Via Squirrel.EXE id: 1e75c1cc-c5d4-42aa-ac3d-91b0b68b3b4c related: - id: 45239e6a-b035-4aaf-b339-8ad379fcb67e type: similar - id: fa4b21c9-0057-4493-b289-2556416ae4d7 type: obsolete status: test description: 'Detects the usage of the "Squirrel.exe" to download arbitrary files. This binary is part of multiple Electron based software installations (Slack, Teams, Discord, etc.) ' references: - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Squirrel/ - http://www.hexacorn.com/blog/2019/03/30/sqirrel-packages-manager-as-a-lolbin-a-k-a-many-electron-apps-are-lolbins-by-default/ - http://www.hexacorn.com/blog/2018/08/16/squirrel-as-a-lolbin/ author: Nasreddine Bencherchali (Nextron Systems), Karneades / Markus Neis, Jonhnathan Ribeiro, oscd.community date: 2022-06-09 modified: 2023-11-09 tags: - attack.execution - attack.stealth - attack.t1218 logsource: category: process_creation product: windows detection: selection_img: Image|endswith: - \squirrel.exe - \update.exe selection_download_cli: CommandLine|contains: - ' --download ' - ' --update ' - ' --updateRollback=' selection_download_http_keyword: CommandLine|contains: http condition: all of selection_* falsepositives: - Expected FP with some Electron based applications such as (1Clipboard, Beaker Browser, Caret, Discord, GitHub Desktop, etc.) level: medium