Adversaries may create or modify systemd services to repeatedly execute malicious payloads as part of persistence. The systemd service manager is commonly used for managing background daemon processes (also known as services) and other system resources.(Citation: Linux man-pages: systemd January 2014)(Citation: Freedesktop.org Linux systemd 29SEP2018) Systemd is the default initialization (init) system on many Linux distributions starting with Debian 8, Ubuntu 15.04, CentOS 7, RHEL 7, Fedora 15, and replaces legacy init systems including SysVinit and Upstart while remaining backwards compatible with the aforementioned init systems.
Systemd utilizes configuration files known as service units to control how services boot and under what conditions. By default, these unit files are stored in the <code>/etc/systemd/system</code> and <code>/usr/lib/systemd/system</code> directories and have the file extension <code>.service</code>. Each service unit file may contain numerous directives that can execute system commands:
Adversaries have used systemd functionality to establish persistent access to victim systems by creating and/or modifying service unit files that cause systemd to execute malicious commands at system boot.(Citation: Anomali Rocke March 2019)
While adversaries typically require root privileges to create/modify service unit files in the <code>/etc/systemd/system</code> and <code>/usr/lib/systemd/system</code> directories, low privilege users can create/modify service unit files in directories such as <code>~/.config/systemd/user/</code> to achieve user-level persistence.(Citation: Rapid7 Service Persistence 22JUNE2016)
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| action.hacking.variety.Abuse of functionality | Abuse of functionality | related-to | T1543.002 | Create or Modify System Process: Systemd Service |
| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| amazon_inspector | Amazon Inspector | technique_scores | T1543.002 | Systemd Service |
Comments
The Amazon Inspector Best Practices assessment package can assess security control "Configure permissions for system directories" that prevents privilege escalation by local users and ensures only the root account can modify/execute system configuration information and binaries. Amazon Inspector does not directly protect against system modifications rather it just checks to see if security controls are in place which can inform decisions around hardening the system. Due to this, the score is capped at Partial.
References
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