Name:Linux Auditd Doas Conf File Creation id:61059783-574b-40d2-ac2f-69b898afd6b4 version:2 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects the creation of the doas.conf file on a Linux host. This file is used by the doas utility to allow standard users to perform tasks as root, similar to sudo. The detection leverages Linux Auditd data, focusing on the creation of the doas.conf file. This activity is significant because it can indicate an attempt to gain elevated privileges, potentially by an adversary. If confirmed malicious, this could allow an attacker to execute commands with root commands with root privileges, leading to full system compromise. Data_source:
-Linux Auditd Path
search:`linux_auditd` type=PATH name ="/etc/doas.conf*" | rename host as dest | stats count min(_time) as firstTime max(_time) as lastTime by name nametype OGID type dest | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)`| `linux_auditd_doas_conf_file_creation_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://wiki.gentoo.org/wiki/Doas -https://www.makeuseof.com/how-to-install-and-use-doas/ 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 Privilege Escalation' - 'Linux Persistence Techniques' - 'Compromised Linux Host' asset_type:Endpoint confidence:80 impact:80 message:A [$type$] event occured on host - [$dest$] to create a doas.conf file. mitre_attack_id: - 'T1548.003' - 'T1548' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'name' - 'nametype' - 'OGID' risk_score:64 security_domain:endpoint
