Name:Linux Auditd Change File Owner To Root id:7b87c556-0ca4-47e0-b84c-6cd62a0a3e90 version:3 date:2024-10-17 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects the use of the 'chown' command to change a file owner to 'root' on a Linux system. It leverages Linux Auditd telemetry, specifically monitoring command-line executions and process details. This activity is significant as it may indicate an attempt to escalate privileges by adversaries, malware, or red teamers. If confirmed malicious, this action could allow an attacker to gain root-level access, leading to full control over the compromised host and potential persistence within the environment. Data_source:
-Linux Auditd Proctitle
search:`linux_auditd` `linux_auditd_normalized_proctitle_process`| rename host as dest | where LIKE (process_exec, "%chown %root%") | stats count min(_time) as firstTime max(_time) as lastTime by process_exec proctitle normalized_proctitle_delimiter dest | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`| `linux_auditd_change_file_owner_to_root_filter`
how_to_implement:To implement this detection, the process begins by ingesting auditd data, that consist SYSCALL, TYPE, EXECVE and PROCTITLE events, which captures command-line executions and process details on Unix/Linux systems. These logs should be ingested and processed using Splunk Add-on for Unix and Linux (https://splunkbase.splunk.com/app/833), which is essential for correctly parsing and categorizing the data. The next step involves normalizing the field names to match the field names set by the Splunk Common Information Model (CIM) to ensure consistency across different data sources and enhance the efficiency of data modeling. This approach enables effective monitoring and detection of linux endpoints where auditd is deployed known_false_positives:Administrator or network operator can execute this command. Please update the filter macros to remove false positives. References: -https://unix.stackexchange.com/questions/101073/how-to-change-permissions-from-root-user-to-all-users -https://askubuntu.com/questions/617850/changing-from-user-to-superuser drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Linux Living Off The Land' - 'Linux Privilege Escalation' - 'Linux Persistence Techniques' - 'Compromised Linux Host' asset_type:Endpoint confidence:80 impact:80 message:A [$process_exec$] event occurred on host - [$dest$] to change a file owner to root. mitre_attack_id: - 'T1222.002' - 'T1222' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'proctitle' risk_score:64 security_domain:endpoint
