Adversaries may establish persistence by modifying RC scripts which are executed during a Unix-like system’s startup. These files allow system administrators to map and start custom services at startup for different run levels. RC scripts require root privileges to modify.

Adversaries can establish persistence by adding a malicious binary path or shell commands to <code>rc.local</code>, <code>rc.common</code>, and other RC scripts specific to the Unix-like distribution.(Citation: IranThreats Kittens Dec 2017)(Citation: Intezer HiddenWasp Map 2019) Upon reboot, the system executes the script's contents as root, resulting in persistence.

Adversary abuse of RC scripts is especially effective for lightweight Unix-like distributions using the root user as default, such as IoT or embedded systems.(Citation: intezer-kaiji-malware)

Several Unix-like systems have moved to Systemd and deprecated the use of RC scripts. This is now a deprecated mechanism in macOS in favor of [Launchd](https://attack.mitre.org/techniques/T1053/004). (Citation: Apple Developer Doco Archive Launchd)(Citation: Startup Items) This technique can be used on Mac OS X Panther v10.3 and earlier versions which still execute the RC scripts.(Citation: Methods of Mac Malware Persistence) To maintain backwards compatibility some systems, such as Ubuntu, will execute the RC scripts if they exist with the correct file permissions.(Citation: Ubuntu Manpage systemd rc)
RC Scripts
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1037/004  external_id: T1037.004     source_name: Apple Developer Doco Archive Launchd  description: Apple. (2016, September 13). Daemons and Services Programming Guide - Creating Launch Daemons and Agents. Retrieved February 24, 2021.  url: https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/CreatingLaunchdJobs.html     source_name: Startup Items  description: Apple. (2016, September 13). Startup Items. Retrieved July 11, 2017.  url: https://developer.apple.com/library/content/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/StartupItems.html     source_name: Ubuntu Manpage systemd rc  description: Canonical Ltd.. (n.d.). systemd-rc-local-generator - Compatibility generator for starting /etc/rc.local and        /usr/sbin/halt.local during boot and shutdown. Retrieved February 23, 2021.  url: http://manpages.ubuntu.com/manpages/bionic/man8/systemd-rc-local-generator.8.html     source_name: IranThreats Kittens Dec 2017  description: Iran Threats . (2017, December 5). Flying Kitten to Rocket Kitten, A Case of Ambiguity and Shared Code. Retrieved May 28, 2020.  url: https://iranthreats.github.io/resources/attribution-flying-rocket-kitten/     source_name: Methods of Mac Malware Persistence  description: Patrick Wardle. (2014, September). Methods of Malware Persistence on Mac OS X. Retrieved July 5, 2017.  url: https://www.virusbulletin.com/uploads/pdf/conference/vb2014/VB2014-Wardle.pdf     source_name: intezer-kaiji-malware  description: Paul Litvak. (2020, May 4). Kaiji: New Chinese Linux malware turning to Golang. Retrieved December 17, 2020.  url: https://www.intezer.com/blog/research/kaiji-new-chinese-linux-malware-turning-to-golang/     source_name: Intezer HiddenWasp Map 2019  description: Sanmillan, I. (2019, May 29). HiddenWasp Malware Stings Targeted Linux Systems. Retrieved June 24, 2019.  url: https://www.intezer.com/blog-hiddenwasp-malware-targeting-linux-systems/     