Name:Linux Auditd Unix Shell Configuration Modification id:66f737c6-3f7f-46ed-8e9b-cc0e5bf01f04 version:9 date:2026-03-12 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects suspicious access or modifications to Unix shell configuration files, which may indicate an attempt to alter system behavior or gain unauthorized access.
Unix shell configuration files, such as `.bashrc` or `.profile`, control user environment settings and command execution.
Unauthorized changes to these files can be used to execute malicious commands, escalate privileges, or hide malicious activities.
By monitoring for unusual or unauthorized modifications to shell configuration files, this analytic helps identify potential security threats, allowing security teams to respond quickly and mitigate risks.
Correlate this with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
Data_source:
-Linux Auditd Path
-Linux Auditd Cwd
search:`linux_auditd` (type=PATH OR type=CWD) | rex "msg=audit\([^)]*:(?<audit_id>\d+)\)"
| stats values(type) as types values(name) as names values(nametype) as nametype values(cwd) as cwd_list values(_time) as event_times by audit_id, host
| stats count min(e_time) as firstTime max(e_time) as lastTime values(nametype) as nametype by current_working_directory reconstructed_path match_count dest audit_id
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 and make sure the type=CWD record type is activate in your auditd configuration.
This approach enables effective monitoring and detection of linux endpoints where auditd is deployed.
known_false_positives:Administrator or network operator can use this application for automation purposes.
Please update the filter macros to remove false positives.
References: -https://www.splunk.com/en_us/blog/security/deep-dive-on-persistence-privilege-escalation-technique-and-detection-in-linux-platform.html -https://github.com/peass-ng/PEASS-ng/tree/master/linPEAS 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' - 'QuietVault' asset_type:Endpoint mitre_attack_id: - 'T1546.004' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
