Basic Input/Output System

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Basic Input/Output System
Technique
ID T1019
Tactic Persistence
Platform Windows Server 2003, Windows Server 2008, Windows Server 2012, Windows XP, Windows 7, Windows 8, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012 R2, Windows Vista, Windows 8.1
Permissions Required Administrator, SYSTEM
Data Sources API monitoring, BIOS
CAPEC ID CAPEC-532

The BIOS (Basic Input/Output System), which underlies the functionality of a computer, may be modified to perform or assist in malicious activity.1

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.

The Unified Extensible Firmware Interface (UEFI) is new specification for the interface between platform firmware and a computer operating system.2

Examples

  • Trojan.Mebromi performs BIOS modification and can download and execute a file as well as protect itself from removal.3
  • Hacking Team UEFI Rootkit is a UEFI BIOS rootkit developed by the company Hacking Team to persist remote access software on some targeted systems.4

Mitigation

Prevent adversary access to privileged accounts or access necessary to perform this technique. Check the integrity of the existing BIOS to determine if it is vulnerable to modification. Patch the BIOS as necessary. Use Trusted Platform Module technology.5

Detection

Firmware manipulation may be detected.6 Dump and inspect BIOS images on vulnerable systems and compare against known good images.7 Analyze differences to determine if malicious changes have occurred. Log attempts to read/write to BIOS and compare against known patching behavior.