T1562.009SubTechniquedefense-evasionagent-callable

T1562.009Safe Mode Boot

Sub-technique of T1562

Platforms: Windows

ATT&CK version: 14.1

What it is

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)

ATT&CK tactics· 1

Defense Evasion

References

  1. https://attack.mitre.org/techniques/T1562/009
  2. https://support.microsoft.com/en-us/windows/start-your-pc-in-safe-mode-in-windows-10-92c27cff-db89-8644-1ce4-b3e5e56fe234
  3. https://news.sophos.com/en-us/2019/12/09/snatch-ransomware-reboots-pcs-into-safe-mode-to-bypass-protection/
  4. https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/bcdedit
  5. https://www.cyberark.com/resources/blog/cyberark-labs-from-safe-mode-to-domain-compromise
  6. https://www.cybereason.com/blog/medusalocker-ransomware
  7. https://www.bleepingcomputer.com/news/security/revil-ransomware-has-a-new-windows-safe-mode-encryption-mode/
  8. https://docs.microsoft.com/windows-server/administration/windows-commands/bootcfg
Sourced from MITRE ATT&CK Enterprise v14.1. Curated and contextualized for EU compliance use cases by Adam Lundqvist, Founder at SQUR.
T1562.009: Safe Mode Boot | SQUR Knowledge Base