Detection rules › Splunk
Linux Service File Created In Systemd Directory
The following analytic detects the creation of suspicious service files within the systemd directories on Linux platforms. It leverages logs containing file name, file path, and process GUID data from endpoints. This activity is significant for a SOC as it may indicate an adversary attempting to establish persistence on a compromised host. If confirmed malicious, this could lead to system compromise or data exfiltration, allowing attackers to maintain control over the system and execute further malicious activities.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1053.006 Scheduled Task/Job: Systemd Timers |
| Persistence | T1053.006 Scheduled Task/Job: Systemd Timers |
| Privilege Escalation | T1053.006 Scheduled Task/Job: Systemd Timers |
Rule body splunk
name: Linux Service File Created In Systemd Directory
id: c7495048-61b6-11ec-9a37-acde48001122
version: 13
creation_date: '2021-12-23'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the creation of suspicious service files within the systemd directories on Linux platforms. It leverages logs containing file name, file path, and process GUID data from endpoints. This activity is significant for a SOC as it may indicate an adversary attempting to establish persistence on a compromised host. If confirmed malicious, this could lead to system compromise or data exfiltration, allowing attackers to maintain control over the system and execute further malicious activities.
data_source:
- Sysmon for Linux EventID 11
search: |-
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem
WHERE Filesystem.file_name = *.service Filesystem.file_path IN ("*/etc/systemd/system*", "*/lib/systemd/system*", "*/usr/lib/systemd/system*", "*/run/systemd/system*", "*~/.config/systemd/*", "*~/.local/share/systemd/*","*/etc/systemd/user*", "*/lib/systemd/user*", "*/usr/lib/systemd/user*", "*/run/systemd/user*")
BY Filesystem.action Filesystem.dest Filesystem.file_access_time
Filesystem.file_create_time Filesystem.file_hash Filesystem.file_modify_time
Filesystem.file_name Filesystem.file_path Filesystem.file_acl
Filesystem.file_size Filesystem.process_guid Filesystem.process_id
Filesystem.user Filesystem.vendor_product
| `drop_dm_object_name(Filesystem)`
| `security_content_ctime(lastTime)`
| `security_content_ctime(firstTime)`
| `linux_service_file_created_in_systemd_directory_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the file name, file path, and process_guid executions from your endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.
known_false_positives: False positives may arise when administrators or network operators create files in systemd directories for legitimate automation tasks. Therefore, it's important to adjust filter macros to account for valid activities. To implement this search successfully, it's crucial to ingest appropriate logs, preferably using the Linux Sysmon Add-on from Splunkbase for those using Sysmon.
references:
- https://attack.mitre.org/techniques/T1053/006/
- https://www.intezer.com/blog/research/kaiji-new-chinese-linux-malware-turning-to-golang/
- https://redcanary.com/blog/attck-t1501-understanding-systemd-service-persistence/
- https://github.com/microsoft/MSTIC-Sysmon/blob/main/linux/configs/attack-based/persistence/T1053.003_Cron_Activity.xml
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 ("$dest$") | 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: 7d
latest_offset: "0"
intermediate_findings:
entities:
- field: dest
type: system
score: 20
message: A service file named as $file_path$ is created in systemd folder on $dest$
analytic_story:
- Linux Privilege Escalation
- Linux Persistence Techniques
- Linux Living Off The Land
- Scheduled Tasks
- Gomir
- China-Nexus Threat Activity
- VoidLink Cloud-Native Linux Malware
asset_type: Endpoint
mitre_attack_id:
- T1053.006
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1053.006/service_systemd/sysmon_linux.log
source: Syslog:Linux-Sysmon/Operational
sourcetype: sysmon:linux
test_type: unit
Stages and Predicates
Stage 1: tstats
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem
WHERE Filesystem.file_name = *.service Filesystem.file_path IN ("*/etc/systemd/system*", "*/lib/systemd/system*", "*/usr/lib/systemd/system*", "*/run/systemd/system*", "*~/.config/systemd/*", "*~/.local/share/systemd/*","*/etc/systemd/user*", "*/lib/systemd/user*", "*/usr/lib/systemd/user*", "*/run/systemd/user*")
BY Filesystem.action Filesystem.dest Filesystem.file_access_time
Filesystem.file_create_time Filesystem.file_hash Filesystem.file_modify_time
Filesystem.file_name Filesystem.file_path Filesystem.file_acl
Filesystem.file_size Filesystem.process_guid Filesystem.process_id
Filesystem.user Filesystem.vendor_product
Stage 2: search
| `drop_dm_object_name(Filesystem)`
Stage 3: search
| `security_content_ctime(lastTime)`
Stage 4: search
| `security_content_ctime(firstTime)`
Stage 5: search
| `linux_service_file_created_in_systemd_directory_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Filesystem.file_name | eq |
|
Filesystem.file_path | in |
|