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). Malicious Component Object Model (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)
View in MITRE ATT&CK®Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name |
---|---|---|---|---|
AC-2 | Account Management | Protects | T1562.009 | Safe Mode Boot |
AC-3 | Access Enforcement | Protects | T1562.009 | Safe Mode Boot |
AC-5 | Separation of Duties | Protects | T1562.009 | Safe Mode Boot |
AC-6 | Least Privilege | Protects | T1562.009 | Safe Mode Boot |
CM-10 | Software Usage Restrictions | Protects | T1562.009 | Safe Mode Boot |
CM-5 | Access Restrictions for Change | Protects | T1562.009 | Safe Mode Boot |
CM-6 | Configuration Settings | Protects | T1562.009 | Safe Mode Boot |
CM-7 | Least Functionality | Protects | T1562.009 | Safe Mode Boot |
IA-2 | Identification and Authentication (organizational Users) | Protects | T1562.009 | Safe Mode Boot |
IA-9 | Service Identification and Authentication | Protects | T1562.009 | Safe Mode Boot |
SC-23 | Session Authenticity | Protects | T1562.009 | Safe Mode Boot |
SC-8 | Transmission Confidentiality and Integrity | Protects | T1562.009 | Safe Mode Boot |
SI-7 | Software, Firmware, and Information Integrity | Protects | T1562.009 | Safe Mode Boot |