This project is dedicated to the analysis of UEFI firmware and system security, providing a structured approach to extracting, inspecting, and understanding the firmware components of a machine. UEFI (Unified Extensible Firmware Interface) serves as the modern replacement for legacy BIOS, playing a crucial role in system initialization, hardware configuration, and Secure Boot enforcement.
By exploring key firmware elements such as the BIOS, EFI System Partition (ESP), UEFI images, and Secure Boot keys, this guide aims to help researchers, security analysts, and developers gain deeper insights into firmware security mechanisms, vulnerabilities, and integrity verification techniques.
The methodology outlined in this project covers the setup of a live analysis environment, extraction of firmware data, and security assessments using industry-standard tools. Whether you're performing a forensic investigation, hunting for vulnerabilities, or validating firmware integrity, this guide serves as a practical resource for navigating UEFI firmware internals.
- Create a live Linux Image
- Boot from USB
- Install Tools
- EFI System Partition (ESP)
- System Firmware (BIOS/UEFI)
- Verify UEFI Images
- UEFI Attack Surface
- Hunting for UEFI Firmware Vulnerabilities
- USB Directory Structure
- Download "Fedora LXDE 64bit"
- Download "Fedora Media Writer"
- Create a Bootable USB
- Run "FedoraMediaWriter-win64-VERSION.exe".
- Accept the terms and follow the installation process.
- Launch Fedora Media Writer after installation.
- Click on "Select .iso file".
- Select "Fedora-LXDE-Live-x86_64-VERSION.iso".
- Choose the USB drive where you want to write the image.
- Click "Write" and wait for the process to complete.
- Click "Finish".
Note: If you encounter any issues creating the bootable USB, try using Rufus or Balena Etcher as alternative tools.
- Enter BIOS/UEFI pressing F2 or F12 during startup.
- Ensure that the Boot Mode is set to "UEFI Only" or "Both".
- Select to boot from DVD or USB.
- Save settings and reboot.
- Select the option "Test this media 8 start Fedora-LXDE-Live VERSION".
- Open System Tools -> LXTerminal.
- Install Dmidecode
- Package
sudo dnf install -y dmidecode - Help
dmidecode --help
- Package
- Install UEFI secure boot verification tool
- Table
| Operating System | Install UEFI secure boot verification tool | |------------------|--------------------------------------------------------| | Windows WSL2 | sudo apt-get update && sudo apt-get install sbsigntool | | Debian | sudo apt-get install sbsigntool | | Ubuntu | sudo apt-get install sbsigntool | | Arch Linux | sudo pacman -S sbsigntools | | Kali Linux | sudo apt-get install sbsigntool | | Fedora | sudo dnf install sbsigntools | | Raspbian | sudo apt-get install sbsigntool | | Dockerfile | dockerfile.run/sbverify | - Package
sudo dnf install -y sbsigntools
- Table
- Install CHIPSEC (Usage, Manual) to analyze the security of PC platforms
- Dependencies
sudo dnf install -y kernel kernel-devel-$(uname -r) python3 python3-devel gcc nasm redhat-rpm-config elfutils-libelf-devel git - Clone
git clone https://github.com/chipsec/chipsec cd chipsec - Requirements
pip install -r linux_requirements.txt - Build
python setup.py build_ext -i - Aliases
sudo ln -s $(pwd)/chipsec_main.py /usr/local/bin/chipsec_main sudo ln -s $(pwd)/chipsec_util.py /usr/local/bin/chipsec_util - Help
chipsec_main --help chipsec_util --help cd
- Dependencies
- Install UEFI Firmware Parser
- Package
sudo pip install uefi_firmware - Help
uefi-firmware-parser --help
- Package
- Install Binwalk
- Package
sudo dnf install binwalk - Help
binwalk --help
- Package
- Install FwHunt Community Scanner and FwHunt Rules
- Dependencies
sudo dnf install -y rizin - Clone
git clone https://github.com/binarly-io/fwhunt-scan cd fwhunt-scan - Build
python setup.py install - Requirements
pip install -r requirements.txt - Rules
git clone https://github.com/binarly-io/FwHunt - Help
fwhunt_scan_analyzer.py --help cd
- Dependencies
- List block devices
lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABELNote: The ESP typically has a FAT (vfat) filesystem and is relatively small in size, like 100M. - Mount ESP
sudo mkdir -p /mnt/esp sudo mount /dev/nvme0n1p1 /mnt/esp tree /mnt/esp - Insert another USB
df -h cd /run/media/liveuser/New\ Volume - BIOS Information
sudo dmidecode --type bios > BIOS.txt cat BIOS.txt - Folders
mkdir 00_LinuxLiveBootloaders mkdir 01_EfiSystemPartition - Copy Linux Live Bootloader Files
sudo cp -r /boot/efi/EFI/ 00_LinuxLiveBootloaders/ tree 00_LinuxLiveBootloaders/ - Copy ESP data
cp -r /mnt/esp/EFI/ 01_EfiSystemPartition/ tree 01_EfiSystemPartition/
- Firmware Acquisition
mkdir 02_FirmwareAcquisition && cd 02_FirmwareAcquisitionsudo chipsec_util spi dump firmware.bincp firmware.bin firmware.backup.bincd .. - EFI Executables
mkdir 03_EfiExecutables && cd 03_EfiExecutablessudo chipsec_main --module tools.uefi.scan_image -a generate,03_EfiExecutables/efilist.json,../02_FirmwareAcquisition/firmware.bincd .. - EFI Configuration
mkdir 04_EfiConfiguration && cd 04_EfiConfigurationsudo chipsec_util uefi var-listcd .. - Secure Boot keys
mkdir 05_SecureBootKeys && cd 05_SecureBootKeyssudo chipsec_util uefi var-find PK sudo chipsec_util uefi var-find db sudo chipsec_util uefi var-find dbx sudo chipsec_util uefi var-find KEK sudo chipsec_util uefi keys PK_*.bin sudo chipsec_util uefi keys db_*.bin sudo chipsec_util uefi keys dbx_*.bin sudo chipsec_util uefi keys KEK_*.bincd .. - Files, Sections and Volumes
mkdir 06_FilesSectionsVolumes && cd 06_FilesSectionsVolumesuefi-firmware-parser --extract ../02_FirmwareAcquisition/firmware.bin fwhunt_scan_analyzer.py extract ../02_FirmwareAcquisition/firmware.bin modules/ binwalk --extract --matryoshka ../02_FirmwareAcquisition/firmware.bincd ..
- Verify bootx64.efi:
cd /mnt/esp/EFI/Boot sbverify --list bootx64.efisignature 1 image signature issuers: - /C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=Microsoft Windows Production PCA 2011 image signature certificates: - subject: /C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=Microsoft Windows issuer: /C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=Microsoft Windows Production PCA 2011 - subject: /C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=Microsoft Windows Production PCA 2011 issuer: /C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=Microsoft Root Certificate Authority 2010 - Folders
mkdir xx_VerifySignedUefiBinaries && cd xx_VerifySignedUefiBinaries - Verify EFI files:
nano verify_efi_files.sh#!/bin/bash EFI_DIR="/mnt/esp/EFI" SUMMARY_FILE="verify_efi_files_summary.txt" # Initialize counters signed_count=0 unsigned_count=0 microsoft_signed_count=0 other_signed_count=0 # Colors RED='\033[0;31m' YELLOW='\033[1;33m' GREEN='\033[0;32m' NC='\033[0m' # No Color # Initialize summary file echo "" > $SUMMARY_FILE echo "UEFI File Verification Summary" >> $SUMMARY_FILE echo "------------------------------" >> $SUMMARY_FILE # Function to check if the file is signed by Microsoft is_microsoft_signed() { issuer="$1" if [[ "$issuer" == *"Microsoft Corporation"* ]]; then return 0 else return 1 fi } # Verify each EFI file and log the results for file in $(find "$EFI_DIR" -type f -name "*.efi"); do echo "----------------------------------------" echo "Verifying $file" output=$(sudo sbverify --list "$file" 2>&1) echo "$output" if echo "$output" | grep -q "No signature table present"; then printf "${RED}%-70s: Possibly Malicious${NC}\n" "$file" printf "%-70s: Possibly Malicious\n" "$file" >> $SUMMARY_FILE ((unsigned_count++)) elif echo "$output" | grep -q "image signature issuers:"; then if is_microsoft_signed "$(echo "$output" | grep "image signature issuers:" -A 1)"; then printf "${GREEN}%-70s: Signed by Microsoft${NC}\n" "$file" printf "%-70s: Signed by Microsoft\n" "$file" >> $SUMMARY_FILE ((microsoft_signed_count++)) else printf "${YELLOW}%-70s: Suspicious (Signed by other entity)${NC}\n" "$file" printf "%-70s: Suspicious (Signed by other entity)\n" "$file" >> $SUMMARY_FILE ((other_signed_count++)) fi ((signed_count++)) else printf "%-70s: Verification failed or unknown signature format\n" "$file" >> $SUMMARY_FILE fi echo "----------------------------------------" done # Print summary echo "------------------------------" >> $SUMMARY_FILE echo "Total EFI files verified: $((signed_count + unsigned_count))" >> $SUMMARY_FILE echo "Signed files: $signed_count" >> $SUMMARY_FILE echo "Unsigned files: $unsigned_count" >> $SUMMARY_FILE echo "Microsoft signed files: $microsoft_signed_count" >> $SUMMARY_FILE echo "Other signed files: $other_signed_count" >> $SUMMARY_FILE # Display summary cat $SUMMARY_FILEchmod +x verify_efi_files.sh ./verify_efi_files.sh cat verify_efi_files_summary.txt cd
- Folder
mkdir xx_UefiAttackSurface && cd xx_UefiAttackSurface - Basic
sudo chipsec_main > output_chipsec_main.txt sudo chipsec_main --json output_chipsec_main.json sudo chipsec_main --markdown output_chipsec_main.mdVisit https://chipsec.github.io/development/Vulnerabilities-and-CHIPSEC-Modules.html to find a list of available CHIPSEC modules-
CHIPSEC test modules return standard values that can be interpreted as follows:
-
Click to Show/Hide Result Meanings
Result Meaning PASSED A mitigation to a known vulnerability has been detected FAILED A known vulnerability has been detected WARNING We have detected something that could be a vulnerability but manual analysis is required to confirm (inconclusive) NOT_APPLICABLE The issue checked by this module is not applicable to this platform. This result can be ignored INFORMATION This module does not check for a vulnerability. It just prints information about the system ERROR Something went wrong in the execution of CHIPSEC
-
-
Known vulnerabilities can be mapped to CHIPSEC modules as follows:
-
Click to Show/Hide UEFI Attack Surface Table
Attack Surface / Vector Vulnerability Description CHIPSEC Module Firmware protections in ROM SMI event configuration is not locked common.bios_smi SPI flash descriptor is not protected common.spi_desc SPI controller security override is enabled common.spi_fdopss SPI flash controller is not locked common.spi_lock Device-specific SPI flash protection is not used chipsec_util spi write (manual analysis) SMM BIOS write protection is not correctly used common.bios_wp Flash protected ranges do not protect BIOS region common.bios_wp BIOS interface is not locked common.bios_ts SMI configuration is not locked (SMI race condition) common.smi_lock Runtime protection of SMRAM Compatibility SMRAM is not locked common.smm SMM cache attack common.smrr Memory remapping vulnerability in SMM protection remap DMA protections of SMRAM are not in use smm_dma Graphics aperture redirection of SMRAM chipsec_util memconfig remap Memory sinkhole vulnerability tools.cpu.sinkhole Secure boot Incorrect protection of secure boot configuration Root certificate common.bios_wp, common.secureboot.variables Key exchange keys and whitelist/blacklist common.secureboot.variables Controls in setup variable (CSM enable/disable, image verification policies, secure boot enable/disable, clear/restore keys) chipsec_util uefi var-find Setup TE header confusion tools.secureboot.te UEFI NVRAM is not write protected common.bios_wp Insecure handling of secure boot disable chipsec_util uefi var-list Persistent firmware configuration Secure boot configuration is stored in unprotected variable common.secureboot.variables, chipsec_util uefi var-list Variable permissions are not set according to specification common.uefi.access_uefispec Sensitive data (like passwords) are stored in UEFI variables chipsec_util uefi var-list (manual analysis) Firmware doesn't sanitize pointers/addresses stored in variables chipsec_util uefi var-list (manual analysis) Firmware hangs on invalid variable content chipsec_util uefi var-write, chipsec_util uefi var-delete (manual analysis) Hardware configuration stored in unprotected variables chipsec_util uefi var-list (manual analysis) Re-creating variables with less restrictive permissions chipsec_util uefi var-write (manual analysis) Variable NVRAM overflow chipsec_util uefi var-write (manual analysis) Critical configuration is stored in unprotected CMOS chipsec_util cmos, common.rtclock Platform hardware configuration Boot block top-swap mode is not locked common.bios_ts Architectural features not locked common.ia32cfg Memory map is not locked memconfig IOMMU usage chipsec_util iommu Memory remapping is not locked remap Runtime firmware (e.g., SMI handlers) SMI handlers use pointers/addresses from OS without validation tools.smm.smm_ptr Legacy SMI handlers call legacy BIOS outside SMRAM INT15 in legacy SMI handlers UEFI SMI handlers call UEFI services outside SMRAM Malicious CommBuffer pointer and contents Race condition during SMI handler Authenticated variables SMI handler is not implemented chipsec_util uefi var-write SmmRuntime vulnerability tools.uefi.blacklist Boot time firmware Software vulnerabilities when parsing, decompressing, and loading data from ROM Software vulnerabilities in implementation of digital signature verification Pointers stored in UEFI variables and used during boot chipsec_util uefi var-write Loading unsigned PCI option ROMs chipsec_util pci xrom Boot hangs due to error condition (e.g., ASSERT) Power state transitions (e.g., resume from sleep) Insufficient protection of S3 boot script table common.uefi.s3bootscript, tools.uefi.s3script_modify Dispatch opcodes in S3 boot script call functions in unprotected memory common.uefi.s3bootscript, tools.uefi.s3script_modify S3 boot script interpreter stored in unprotected memory Pointer to S3 boot script table in unprotected UEFI variable common.uefi.s3bootscript, tools.uefi.s3script_modify Critical setting not recorded in S3 boot script table chipsec_util uefi s3bootscript (manual analysis) OS waking vector in ACPI tables can be modified chipsec_util acpi dump (manual analysis) Using pointers on S3 resume stored in unprotected UEFI variables chipsec_util uefi var-write Firmware update Software vulnerabilities when parsing firmware updates Unauthenticated firmware updates Runtime firmware update that can be interrupted Signature not checked on capsule update executable Network interfaces Software vulnerabilities when handling messages over network interfaces Booting unauthenticated firmware over unprotected network interfaces Misc BIOS keyboard buffer is not cleared during boot common.bios_kbrd_buffer DMA attack from devices during firmware execution
-
-
- SPI Info
sudo chipsec_util spi info sudo chipsec_util spi info > output_spi_info.txt
- Folder
mkdir xx_FirmwareVulnerabilities && cd xx_FirmwareVulnerabilities - Find Vulnerabilities, Generate SBOMs & CBOMs
Visit https://risk.binarly.io/ Upload firmware to https://risk.binarly.io/scan - Scan Firmware
fwhunt_scan_analyzer.py scan-firmware --rules_dir $HOME/fwhunt-scan/FwHunt/rules/Vulnerabilities/Lenovo/ ../02_FirmwareAcquisition/firmware.bin
├───New Volume
|
├───00_LinuxLiveBootloaders
├───01_EfiSystemPartition
├───02_FirmwareAcquisition
├───03_EfiExecutables
├───04_EfiConfiguration
├───05_SecureBootKeys
├───06_FilesSectionsVolumes
|
├───xx_VerifySignedUefiBinaries
├───xx_UefiAttackSurface
└───xx_FirmwareVulnerabilities