Query: alert when Detects a network connection that is initiated by the "notepad.exe" process. This might be a sign of process injection f
Matching passage: Sigma rule: Detects a network connection that is initiated by the "notepad.exe" process. This might be a sign of process injection f. Logsource: windows / network_connection. Rule: title: Network Connection Initiated Via Notepad.EXE id: e81528db-fc02-45e8-8e98-4e84aba1f10b status: test description: 'Detects a network connection that is initiated by the "notepad.exe" process. This might be a sign of process injection from a beacon process or something similar. Notepad rarely initiates a network communication except when printing documents for example. ' references: - https://web.archive.org/web/20200219102749/https://www.sans.org/cyber-security-summit/archives/file/summit-archive-1492186586.pdf - https://www.cobaltstrike.com/blog/why-is-notepad-exe-connecting-to-the-internet author: EagleEye Team date: 2020-05-14 modified: 2024-02-02 tags: - attack.privilege-escalation - attack.command-and-control - attack.execution - attack.stealth - attack.t1055 logsource: category: network_connection product: windows detection: selection: Image|endswith: \notepad.exe filter_optional_printing: DestinationPort: 9100 condition: selection and not 1 of filter_optional_* falsepositives: - Printing documents via notepad might cause communication with the printer via port 9100 or similar. level: high
Near-miss 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