Adversaries may abuse Windows safe mode to disable endpoint defenses. Safe mode starts up the Windows operating system with a limited set of drivers and services. Third-party security software such as endpoint detection and response (EDR) tools may not start after booting Windows in safe mode. There are two versions of safe mode: Safe Mode and Safe Mode with Networking. It is possible to start additional services after a safe mode boot.(Citation: Microsoft Safe Mode)(Citation: Sophos Snatch Ransomware 2019)

Adversaries may abuse safe mode to disable endpoint defenses that may not start with a limited boot. Hosts can be forced into safe mode after the next reboot via modifications to Boot Configuration Data (BCD) stores, which are files that manage boot application settings.(Citation: Microsoft bcdedit 2021)

Adversaries may also add their malicious applications to the list of minimal services that start in safe mode by modifying relevant Registry values (i.e. [Modify Registry](https://attack.mitre.org/techniques/T1112)). Malicious [Component Object Model](https://attack.mitre.org/techniques/T1559/001) (COM) objects may also be registered and loaded in safe mode.(Citation: Sophos Snatch Ransomware 2019)(Citation: CyberArk Labs Safe Mode 2016)(Citation: Cybereason Nocturnus MedusaLocker 2020)(Citation: BleepingComputer REvil 2021)
Safe Mode Boot
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1562/009  external_id: T1562.009     source_name: Microsoft Safe Mode  description: Microsoft. (n.d.). Start your PC in safe mode in Windows 10. Retrieved June 23, 2021.  url: https://support.microsoft.com/en-us/windows/start-your-pc-in-safe-mode-in-windows-10-92c27cff-db89-8644-1ce4-b3e5e56fe234     source_name: Sophos Snatch Ransomware 2019  description: Sophos. (2019, December 9). Snatch ransomware reboots PCs into Safe Mode to bypass protection. Retrieved June 23, 2021.  url: https://news.sophos.com/en-us/2019/12/09/snatch-ransomware-reboots-pcs-into-safe-mode-to-bypass-protection/     source_name: Microsoft bcdedit 2021  description: Microsoft. (2021, May 27). bcdedit. Retrieved June 23, 2021.  url: https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/bcdedit     source_name: CyberArk Labs Safe Mode 2016  description: Naim, D.. (2016, September 15). CyberArk Labs: From Safe Mode to Domain Compromise. Retrieved June 23, 2021.  url: https://www.cyberark.com/resources/blog/cyberark-labs-from-safe-mode-to-domain-compromise     source_name: Cybereason Nocturnus MedusaLocker 2020  description: Cybereason Nocturnus. (2020, November 19). Cybereason vs. MedusaLocker Ransomware. Retrieved June 23, 2021.  url: https://www.cybereason.com/blog/medusalocker-ransomware     source_name: BleepingComputer REvil 2021  description: Abrams, L. (2021, March 19). REvil ransomware has a new ‘Windows Safe Mode’ encryption mode. Retrieved June 23, 2021.  url: https://www.bleepingcomputer.com/news/security/revil-ransomware-has-a-new-windows-safe-mode-encryption-mode/     source_name: Microsoft Bootcfg  description: Gerend, J. et al. (2017, October 16). bootcfg. Retrieved August 30, 2021.  url: https://docs.microsoft.com/windows-server/administration/windows-commands/bootcfg     