System Firmware
The BIOS (Basic Input/Output System) and The Unified Extensible Firmware Interface (UEFI) or Extensible Firmware Interface (EFI) are examples of system firmware that operate as the software interface between the operating system and hardware of a computer. (Citation: Wikipedia BIOS) (Citation: Wikipedia UEFI) (Citation: About UEFI) System firmware like BIOS and (U)EFI underly the functionality of a computer and may be modified by an adversary to perform or assist in malicious activity. Capabilities exist to overwrite the system firmware, which may give sophisticated adversaries a means to install malicious firmware updates as a means of persistence on a system that may be difficult to detect.
Procedure Examples |
|
| Name | Description |
|---|---|
| LoJax |
LoJax is a UEFI BIOS rootkit deployed to persist remote access software on some targeted systems.(Citation: ESET LoJax Sept 2018) |
| Hacking Team UEFI Rootkit |
Hacking Team UEFI Rootkit is a UEFI BIOS rootkit developed by the company Hacking Team to persist remote access software on some targeted systems.(Citation: TrendMicro Hacking Team UEFI) |
| Trojan.Mebromi |
Trojan.Mebromi performs BIOS modification and can download and execute a file as well as protect itself from removal.(Citation: Ge 2011) |
Mitigations |
|
| Mitigation | Description |
|---|---|
| Update Software |
Perform regular software updates to mitigate exploitation risk. |
| Boot Integrity |
Use secure methods to boot a system and verify the integrity of the operating system and loading mechanisms. |
| Privileged Account Management |
Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root. |
| System Firmware Mitigation |
Prevent adversary access to privileged accounts or access necessary to perform this technique. Check the integrity of the existing BIOS or EFI to determine if it is vulnerable to modification. Patch the BIOS and EFI as necessary. Use Trusted Platform Module technology. (Citation: TCG Trusted Platform Module) |
Detection
System firmware manipulation may be detected. (Citation: MITRE Trustworthy Firmware Measurement) Dump and inspect BIOS images on vulnerable systems and compare against known good images. (Citation: MITRE Copernicus) Analyze differences to determine if malicious changes have occurred. Log attempts to read/write to BIOS and compare against known patching behavior. Likewise, EFI modules can be collected and compared against a known-clean list of EFI executable binaries to detect potentially malicious modules. The CHIPSEC framework can be used for analysis to determine if firmware modifications have been performed. (Citation: McAfee CHIPSEC Blog) (Citation: Github CHIPSEC) (Citation: Intel HackingTeam UEFI Rootkit)
References
- ESET. (2018, September). LOJAX First UEFI rootkit found in the wild, courtesy of the Sednit group. Retrieved July 2, 2019.
- Trusted Computing Group. (2008, April 29). Trusted Platform Module (TPM) Summary. Retrieved June 8, 2016.
- Lin, P. (2015, July 13). Hacking Team Uses UEFI BIOS Rootkit to Keep RCS 9 Agent in Target Systems. Retrieved December 11, 2015.
- Ge, L. (2011, September 9). BIOS Threat is Showing up Again!. Retrieved November 14, 2014.
- Intel Security. (2005, July 16). HackingTeam's UEFI Rootkit Details. Retrieved March 20, 2017.
- Intel. (2017, March 18). CHIPSEC Platform Security Assessment Framework. Retrieved March 20, 2017.
- Beek, C., Samani, R. (2017, March 8). CHIPSEC Support Against Vault 7 Disclosure Scanning. Retrieved March 13, 2017.
- Butterworth, J. (2013, July 30). Copernicus: Question Your Assumptions about BIOS Security. Retrieved December 11, 2015.
- Upham, K. (2014, March). Going Deep into the BIOS with MITRE Firmware Security Research. Retrieved January 5, 2016.
- UEFI Forum. (n.d.). About UEFI Forum. Retrieved January 5, 2016.
- Wikipedia. (2017, July 10). Unified Extensible Firmware Interface. Retrieved July 11, 2017.
- Wikipedia. (n.d.). BIOS. Retrieved January 5, 2016.
Связанные риски
Каталоги
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