Query: alert when Detects the creation or modification of files within the "sudoers.d" directory on Linux systems. Such activity may indic
Matching passage: Sigma rule: Detects the creation or modification of files within the "sudoers.d" directory on Linux systems. Such activity may indic. Logsource: linux / file_event. Rule: title: Persistence Via Sudoers.d Files id: ddb26b76-4447-4807-871f-1b035b2bfa5d status: test description: 'Detects the creation or modification of files within the "sudoers.d" directory on Linux systems. Such activity may indicate an attempt to establish or maintain privilege escalation by granting specific users elevated permissions. Unauthorized changes to sudoers files are a common technique used by attackers to persist administrative access. ' references: - https://github.com/h3xduck/TripleCross/blob/1f1c3e0958af8ad9f6ebe10ab442e75de33e91de/apps/deployer.sh author: Nasreddine Bencherchali (Nextron Systems) date: 2022-07-05 modified: 2026-03-18 tags: - attack.privilege-escalation - attack.persistence - attack.t1548.003 logsource: product: linux category: file_event detection: selection: TargetFilename|startswith: /etc/sudoers.d/ filter_main_dpkg: Image|endswith: /usr/bin/dpkg TargetFilename: /etc/sudoers.d/README.dpkg-new condition: selection and not 1 of filter_main_* falsepositives: - Creation of legitimate files in sudoers.d folder as part of administrator work level: medium
Near-miss passage: Sigma rule: Detects the use of Ngrok, a utility used for port forwarding and tunneling, often used by threat actors to make local pr. Logsource: windows / process_creation. Rule: title: PUA - Ngrok Execution id: ee37eb7c-a4e7-4cd5-8fa4-efa27f1c3f31 status: test description: 'Detects the use of Ngrok, a utility used for port forwarding and tunneling, often used by threat actors to make local protected services publicly available. Involved domains are bin.equinox.io for download and *.ngrok.io for connections. ' references: - https://ngrok.com/docs - https://www.fireeye.com/blog/threat-research/2021/05/shining-a-light-on-darkside-ransomware-operations.html - https://stackoverflow.com/questions/42442320/ssh-tunnel-to-ngrok-and-initiate-rdp - https://www.virustotal.com/gui/file/58d21840d915aaf4040ceb89522396124c82f325282f805d1085527e1e2ccfa1/detection - https://cybleinc.com/2021/02/15/ngrok-platform-abused-by-hackers-to-deliver-a-new-wave-of-phishing-attacks/ - https://twitter.com/xorJosh/status/1598646907802451969 - https://www.softwaretestinghelp.com/how-to-use-ngrok/ author: Florian Roth (Nextron Systems) date: 2021-05-14 modified: 2023-02-21 tags: - attack.command-and-control - attack.t1572 logsource: category: process_creation product: windows detection: selection1: CommandLine|contains: - ' tcp 139' - ' tcp 445' - ' tcp 3389' - ' tcp 5985' - ' tcp 5986' selection2: CommandLine|contains|all: - ' start ' - --all - --config - .yml selection3: Image|endswith: ngrok.exe CommandLine|contains: - ' tcp ' - ' http ' - ' authtoken ' selection4: CommandLine|contains: - '.exe authtoken ' - .exe start --all condition: 1 of selection* falsepositives: - Another tool that uses the command line switches of Ngrok - Ngrok http 3978 (https://learn.microsoft.com/en-us/azure/bot-service/bot-service-debug-channel-ngrok?view=azure-bot-service-4.0) level: high