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https://github.com/splunk/security_content
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Eric
81 lines
4.2 KiB
YAML
81 lines
4.2 KiB
YAML
name: Linux Setuid Using Chmod Utility
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id: bf0304b6-6250-11ec-9d7c-acde48001122
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version: 7
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date: '2025-05-02'
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author: Teoderick Contreras, Splunk
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status: production
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type: Anomaly
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description: The following analytic detects the execution of the chmod utility to
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set the SUID or SGID bit on files, which can allow users to temporarily gain root
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or group-level access. This detection leverages data from Endpoint Detection and
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Response (EDR) agents, focusing on process names and command-line arguments related
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to chmod. This activity is significant as it can indicate an attempt to escalate
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privileges or maintain persistence on a system. If confirmed malicious, an attacker
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could gain elevated access, potentially compromising sensitive data or critical
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system functions.
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data_source:
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- Sysmon for Linux EventID 1
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search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
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as lastTime from datamodel=Endpoint.Processes WHERE (Processes.process_name = chmod
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OR Processes.process = "*chmod *") AND Processes.process IN("* g+s *", "* u+s *",
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"* 4777 *", "* 4577 *") by Processes.action Processes.dest Processes.original_file_name
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Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
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Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
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Processes.process Processes.process_exec Processes.process_guid Processes.process_hash
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Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path
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Processes.user Processes.user_id Processes.vendor_product | `drop_dm_object_name(Processes)`
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| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_setuid_using_chmod_utility_filter`'
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how_to_implement: The detection is based on data that originates from Endpoint Detection
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and Response (EDR) agents. These agents are designed to provide security-related
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telemetry from the endpoints where the agent is installed. To implement this search,
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you must ingest logs that contain the process GUID, process name, and parent process.
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Additionally, you must ingest complete command-line executions. These logs must
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be processed using the appropriate Splunk Technology Add-ons that are specific to
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the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
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data model. Use the Splunk Common Information Model (CIM) to normalize the field
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names and speed up the data modeling process.
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known_false_positives: Administrator or network operator can execute this command.
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Please update the filter macros to remove false positives.
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references:
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- https://www.hackingarticles.in/linux-privilege-escalation-using-capabilities/
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drilldown_searches:
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- name: View the detection results for - "$dest$"
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search: '%original_detection_search% | search dest = "$dest$"'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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- name: View risk events for the last 7 days for - "$dest$"
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search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$")
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starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime
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values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories)
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as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic)
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as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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rba:
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message: a commandline $process$ that may set suid or sgid on $dest$
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risk_objects:
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- field: dest
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type: system
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score: 49
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threat_objects: []
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tags:
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analytic_story:
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- Linux Privilege Escalation
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- Linux Persistence Techniques
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- Linux Living Off The Land
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asset_type: Endpoint
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mitre_attack_id:
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- T1548.001
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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security_domain: endpoint
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tests:
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- name: True Positive Test
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attack_data:
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- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548.001/chmod_uid/sysmon_linux.log
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source: Syslog:Linux-Sysmon/Operational
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sourcetype: sysmon:linux
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