Query: Sigma rule for Detects the creation of cron files in Cron directories, which could indicate potential persistence mechanisms being esta
Matching passage: Sigma rule: Detects the creation of cron files in Cron directories, which could indicate potential persistence mechanisms being esta. Logsource: linux / file_event. Rule: title: New Cron File Created id: 6c4e2f43-d94d-4ead-b64d-97e53fa2bd05 status: experimental description: 'Detects the creation of cron files in Cron directories, which could indicate potential persistence mechanisms being established by an attacker. Note that not all cron file creations are malicious - legitimate system administration activities and software installations may also create cron files. This detection should be investigated in context, considering factors such as the user creating the file, the timing of creation, and the contents of the cron job. Focus investigation on unexpected cron files created by non-administrative users or during suspicious timeframes. Additionally, it is recommended to review the contents of the newly created cron files to assess their intent. Furthermore, it is suggested to baseline normal cron file creation and apply additional filters to reduce false positives based on the specific environment. ' references: - https://github.com/microsoft/MSTIC-Sysmon/blob/f1477c0512b0747c1455283069c21faec758e29d/linux/configs/attack-based/persistence/T1053.003_Cron_Activity.xml - https://pberba.github.io/security/2022/01/30/linux-threat-hunting-for-persistence-systemd-timers-cron/ - https://www.elastic.co/security-labs/primer-on-persistence-mechanisms - https://snehbavarva.medium.com/privilege-escalation-techniques-series-linux-cron-jobs-a5b797b424b4 author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC date: 2021-10-15 modified: 2026-04-28 tags: - attack.privilege-escalation - attack.execution - attack.persistence - attack.t1053.003 logsource: product: linux category: file_event detection: selection_cron_dirs: TargetFilename|startswith: - /etc/cron.d/ - /etc/cron.daily/ - /etc/cron.hourly/ - /etc/cron.monthly/ - /etc/cron.weekly/ - /var/spool/cron/crontabs/ - /var/spool/cron/root selection_cron_special_files: TargetFilename|contains: - /etc/cron.allow - /etc/cron.deny - /etc/crontab filter_optional_legit_cron: TargetFilename: - /etc/cron.daily/apt - /etc/cron.daily/dpkg - /etc/cron.daily/passwd - /etc/crontabs/root condition: 1 of selection_* and not 1 of filter_optional_* falsepositives: - Legitimate administrative tasks, package managers, containers, configuration management tools, cloud agents, or system maintenance operations might cause false positives. Apply baselining before deployment. level: low
Near-miss passage: Sigma rule: Detects a suspicious process creation as SYSTEM user (suspicious program or command line parameter). Logsource: windows / process_creation. Rule: title: Suspicious SYSTEM User Process Creation id: 2617e7ed-adb7-40ba-b0f3-8f9945fe6c09 status: test description: Detects a suspicious process creation as SYSTEM user (suspicious program or command line parameter) references: - Internal Research - https://tools.thehacker.recipes/mimikatz/modules author: Florian Roth (Nextron Systems), David ANDRE (additional keywords) date: 2021-12-20 modified: 2025-10-19 tags: - attack.credential-access - attack.privilege-escalation - attack.stealth - attack.t1134 - attack.t1003 - attack.t1027 logsource: category: process_creation product: windows detection: selection: IntegrityLevel: - System - S-1-16-16384 User|contains: - AUTHORI - AUTORI selection_special: - Image|endswith: - \calc.exe - \cscript.exe - \forfiles.exe - \hh.exe - \mshta.exe - \ping.exe - \wscript.exe - CommandLine|re: net\s+user\s+ - CommandLine|contains: - ' -NoP ' - ' -W Hidden ' - ' -decode ' - ' /decode ' - ' /urlcache ' - ' -urlcache ' - ' -e* JAB' - ' -e* SUVYI' - ' -e* SQBFAFgA' - ' -e* aWV4I' - ' -e* IAB' - ' -e* PAA' - ' -e* aQBlAHgA' - vssadmin delete shadows - reg SAVE HKLM - ' -ma ' - Microsoft\Windows\CurrentVersion\Run - .downloadstring( - .downloadfile( - ' /ticket:' - 'dpapi::' - event::clear - event::drop - id::modify - 'kerberos::' - 'lsadump::' - 'misc::' - 'privilege::' - 'rpc::' - 'sekurlsa::' - 'sid::' - 'token::' - vault::cred - vault::list - ' p::d ' - ;iex( - MiniDump filter_main_ping: CommandLine|contains|all: - ping - 127.0.0.1 - ' -n ' filter_vs: Image|endswith: \PING.EXE ParentCommandLine|contains: \DismFoDInstall.cmd filter_config_mgr: ParentImage|contains: :\Packages\Plugins\Microsoft.GuestConfiguration.ConfigurationforWindows\ filter_java: ParentImage|contains: - :\Program Files (x86)\Java\ - :\Program Files\Java\ ParentImage|endswith: \bin\javaws.exe Image|contains: - :\Program Files (x86)\Java\ - :\Program Files\Java\ Image|endswith: \bin\jp2launcher.exe CommandLine|contains: ' -ma ' condition: all of selection* and not 1 of filter_* falsepositives: - Administrative activity - Scripts and administrative tools used in the monitored environment - Monitoring activity level: high