Query: rule covering Detects the use of curl with NTLM authentication and empty credentials (-u :), which can be abused to leak the currently
Matching passage: Sigma rule: Detects the use of curl with NTLM authentication and empty credentials (-u :), which can be abused to leak the currently. Logsource: windows / process_creation. Rule: title: NTLM Hash Leak Via Curl NTLM Authentication id: 916eb839-895e-47f8-99ee-3008bf377a3e status: test description: 'Detects the use of curl with NTLM authentication and empty credentials (-u :), which can be abused to leak the currently logged-in user''s NTLMv2 challenge-response to an attacker-controlled server, enabling offline cracking or relay attacks. When no credentials are provided, the Microsoft-shipped curl passes a NULL identity to Windows SSPI, which automatically falls back to the current user''s logon session credentials stored in LSASS — without requiring a plaintext password. This behavior is exclusive to the curl binary shipped by Microsoft (available since Windows 10 / Windows Server 2019), which is built with SSPI support. ' references: - https://github.com/curl/curl/blob/master/lib/vauth/ntlm_sspi.c#L128-L140 - https://learn.microsoft.com/en-us/windows/win32/secauthn/acquirecredentialshandle--ntlm - https://curl.se/docs/manpage.html#--ntlm author: Swachchhanda Shrawan Poudel (Nextron Systems) date: 2026-06-04 tags: - attack.credential-access - attack.t1187 logsource: category: process_creation product: windows detection: selection_img: - Image|endswith: \curl.exe - OriginalFileName: curl.exe selection_ntlm_flag: CommandLine|contains: --ntlm selection_empty_creds: CommandLine|re: '(?i)\s(-u|--user)\s*:' condition: all of selection_* falsepositives: - Should be very rare as it's not widely known or used, but could occur in legitimate use cases where curl is used with NTLM authentication and empty credentials, such as in certain scripts or automation tasks. level: high regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_curl_ntlm_hash_leak_attempt/info.yml
Near-miss passage: Sigma rule: Detects suspicious PowerShell invocation with a parameter substring. Logsource: windows / process_creation. Rule: title: Suspicious PowerShell Parameter Substring id: 36210e0d-5b19-485d-a087-c096088885f0 status: test description: Detects suspicious PowerShell invocation with a parameter substring references: - http://www.danielbohannon.com/blog-1/2017/3/12/powershell-execution-argument-obfuscation-how-it-can-make-detection-easier author: Florian Roth (Nextron Systems), Daniel Bohannon (idea), Roberto Rodriguez (Fix) date: 2019-01-16 modified: 2022-07-14 tags: - attack.execution - attack.t1059.001 logsource: category: process_creation product: windows detection: selection: Image|endswith: - \powershell.exe - \pwsh.exe CommandLine|contains: - ' -windowstyle h ' - ' -windowstyl h' - ' -windowsty h' - ' -windowst h' - ' -windows h' - ' -windo h' - ' -wind h' - ' -win h' - ' -wi h' - ' -win h ' - ' -win hi ' - ' -win hid ' - ' -win hidd ' - ' -win hidde ' - ' -NoPr ' - ' -NoPro ' - ' -NoProf ' - ' -NoProfi ' - ' -NoProfil ' - ' -nonin ' - ' -nonint ' - ' -noninte ' - ' -noninter ' - ' -nonintera ' - ' -noninterac ' - ' -noninteract ' - ' -noninteracti ' - ' -noninteractiv ' - ' -ec ' - ' -encodedComman ' - ' -encodedComma ' - ' -encodedComm ' - ' -encodedCom ' - ' -encodedCo ' - ' -encodedC ' - ' -encoded ' - ' -encode ' - ' -encod ' - ' -enco ' - ' -en ' - ' -executionpolic ' - ' -executionpoli ' - ' -executionpol ' - ' -executionpo ' - ' -executionp ' - ' -execution bypass' - ' -executio bypass' - ' -executi bypass' - ' -execut bypass' - ' -execu bypass' - ' -exec bypass' - ' -exe bypass' - ' -ex bypass' - ' -ep bypass' - ' /windowstyle h ' - ' /windowstyl h' - ' /windowsty h' - ' /windowst h' - ' /windows h' - ' /windo h' - ' /wind h' - ' /win h' - ' /wi h' - ' /win h ' - ' /win hi ' - ' /win hid ' - ' /win hidd ' - ' /win hidde ' - ' /NoPr ' - ' /NoPro ' - ' /NoProf ' - ' /NoProfi ' - ' /NoProfil ' - ' /nonin ' - ' /nonint ' - ' /noninte ' - ' /noninter ' - ' /nonintera ' - ' /noninterac ' - ' /noninteract ' - ' /noninteracti ' - ' /noninteractiv ' - ' /ec ' - ' /encodedComman ' - ' /encodedComma ' - ' /encodedComm ' - ' /encodedCom ' - ' /encodedCo ' - ' /encodedC ' - ' /encoded ' - ' /encode ' - ' /encod ' - ' /enco ' - ' /en ' - ' /executionpolic ' - ' /executionpoli ' - ' /executionpol ' - ' /executionpo ' - ' /executionp ' - ' /execution bypass' - ' /executio bypass' - ' /executi bypass' - ' /execut bypass' - ' /execu bypass' - ' /exec bypass' - ' /exe bypass' - ' /ex bypass' - ' /ep bypass' condition: selection falsepositives: - Unknown level: high