Intel CPU Backdoor Report, Jan 22 2018

Intel CPU Backdoor Report

Change log:
2018/01/01 - Added 14 Useful Links. Disable Intel ME via undocumented NSA "High Assurance Platform" mode with me_cleaner, Blackhat Dec 2017 Intel ME presentation, Intel ME CVEs (CVSS Scored 7.2-10.0)

Intel CPU Backdoor Report
The goal of this report is to make the existence of Intel CPU backdoors a common knowledge and provide information on backdoor removal.

What we know about Intel CPU backdoors so far:

TL;DR version

Your Intel CPU and Chipset is running a backdoor as we speak.

The backdoor hardware is inside the CPU/Bridge and the backdoor firmware (Intel Management Engine) is in the chipset flash memory.

30C3 Intel ME live hack:
[Video] 30C3: Persistent, Stealthy, Remote-controlled Dedicated Hardware Malware [youtube.com]
@21:43, keystrokes leaked from Intel ME above the OS, wireshark failed to detect packets.

[Quotes] Vortrag [events.ccc.de]:
"the ME provides a perfect environment for undetectable sensitive data leakage on behalf of the attacker".

"We can permanently monitor the keyboard buffer on both operating system targets."

Decoding Intel backdoors:
The situation is out of control and the Libreboot/Coreboot community is looking for BIOS/Firmware experts to help with the Intel ME decoding effort.

If you are skilled in these areas, download Intel ME firmwares from this collection [win-raid.com] and have a go at them, beware Intel is using a lot of counter measures to prevent their backdoors from being decoded (explained below).

Backdoor removal:
The backdoor firmware can be removed by following this guide [github.io] using the me_cleaner [github.com] script.
Removal requires a Raspberry Pi (with GPIO pins) and a SOIC clip.

2017 Dec Update:
Intel ME on recent CPUs may be disabled by enabling the undocumented NSA HAP mode [ptsecurity.com], use me_cleaner [github.com] with -S option to set the HAP bit, see me_cleaner: HAP AltMeDisable bit [github.com].

Useful links (Added 2018 Jan 1):
Disabling Intel ME 11 via undocumented HAP mode (NSA High Assurance Platform mode) [ptsecurity.com]
me_cleaner: Set HAP AltMeDisable bit with -S option [github.com]
Blackhat 2017: How To Hack A Turned Off Computer Or Running Unsigned Code In Intel Management Engine [blackhat.com]
EFF: Intel's Management Engine is a security hazard, and users need a way to disable it [eff.org]
Sakaki's EFI Install Guide/Disabling the Intel Management Engine [gentoo.org]
Intel ME bug storm: Hardware vendors race to identify and provide updates for dangerous Intel flaws. [zdnet.com]
CVE-2017-5689 [cvedetails.com]: An unprivileged network attacker could gain system privileges to provisioned Intel manageability SKUs
CVE-2017-5705 [cvedetails.com]: Multiple buffer overflows in kernel in Intel Manageability Engine Firmware
CVE-2017-5706 [cvedetails.com]: Multiple buffer overflows in kernel in Intel Server Platform Services Firmware
CVE-2017-5707 [cvedetails.com]: Multiple buffer overflows in kernel in Intel Trusted Execution Engine Firmware
CVE-2017-5708 [cvedetails.com]: Multiple privilege escalations in kernel in Intel Manageability Engine Firmware
CVE-2017-5709 [cvedetails.com]: Multiple privilege escalations in kernel in Intel Server Platform Services Firmware
CVE-2017-5710 [cvedetails.com]: Multiple privilege escalations in kernel in Intel Trusted Execution Engine Firmware
CVE-2017-5711 [cvedetails.com]: Multiple buffer overflows in Active Management Technology (AMT)
CVE-2017-5712 [cvedetails.com]: Buffer overflow in Active Management Technology (AMT)

Useful links (Added 2017):
The Intel ME subsystem can take over your machine, can't be audited [ycombinator.com]
REcon 2014 - Intel Management Engine Secrets [youtube.com]
Untrusting the CPU (33c3) [youtube.com]
Towards (reasonably) trustworthy x86 laptops [youtube.com]
30C3 To Protect And Infect - The militarization of the Internet [youtube.com]
30c3: To Protect And Infect Part 2 - Mass Surveillance Tools & Software [youtube.com]

1. Introduction, what is Intel ME

Short version, from Intel staff:

Re: What Intel CPUs lack Intel ME secondary processor? [intel.com]
Amy_Intel Feb 8, 2016 9:27 AM

The Management Engine (ME) is an isolated and protected coprocessor, embedded as a non-optional part in all current Intel chipsets, I even checked with the engineering department and they confirmed it.

Long version:

ME: Management Engine [libreboot.org]

The Intel Management Engine (ME) is a separate computing environment physically located in the MCH chip or PCH chip replacing ICH.

The ME consists of an individual processor core, code and data caches, a timer, and a secure internal bus to which additional devices are connected, including a cryptography engine, internal ROM and RAM, memory controllers, and a direct memory access (DMA) engine to access the host operating system's memory as well as to reserve a region of protected external memory to supplement the ME's limited internal RAM. The ME also has network access with its own MAC address through the Intel Gigabit Ethernet Controller integrated in the southbridge (ICH or PCH).

The Intel Management Engine with its proprietary firmware has complete access to and control over the PC: it can power on or shut down the PC, read all open files, examine all running applications, track all keys pressed and mouse movements, and even capture or display images on the screen. And it has a network interface that is demonstrably insecure, which can allow an attacker on the network to inject rootkits that completely compromise the PC and can report to the attacker all activities performed on the PC. It is a threat to freedom, security, and privacy that can't be ignored.

ME firmware versions 6.0 and later, which are found on all systems with an Intel Core i3/i5/i7 CPU and a PCH, include "ME Ignition" firmware that performs some hardware initialization and power management. If the ME's boot ROM does not find in the SPI flash memory an ME firmware manifest with a valid Intel signature, the whole PC will shut down after 30 minutes.

Quotes on Intel backdoors:

A message from RMS [fsf.org]
by Richard Stallman on Dec 29, 2016 09:45 AM

The current generation of Intel and AMD processor chips are designed with vicious back doors that users cannot shut off. (In Intel processors, it's the "management engine".)

No users should trust those processors.

2. The backdoor is next to impossible to decode and reverse engineer:

Due to multiple instruction sets + custom compression algorithm.

The Trouble With Intel's Management Engine [hackaday.com]

While most of the firmware for the ME also resides in the Flash chip used by the BIOS, the firmware isn't readily readable; some common functions are in an on-chip ROM and cannot be found by simply dumping the data from the Flash chip.

This means that if you're trying to figure out the ME, a lot of the code is seemingly missing. Adding to the problem, a lot of the code itself is compressed with either LZMA or Huffman encoding. There are multiple versions of the Intel ME, as well, all using completely different instruction sets: ARC, ARCompact, and SPARC V8. In short, it's a reverse-engineer's worst nightmare.

To break the Management Engine, though, this code will have to be reverse engineered, and figuring out the custom compression scheme that's used in the firmware remains an unsolved problem.

But unsolved doesn't mean that people aren't working on it. There are efforts to break the ME's Huffman algorithm. Of course, deciphering the code we have would lead to another road block: there is still the code on the inaccessible on-chip ROM. Nothing short of industrial espionage or decapping the chip and looking at the silicon will allow anyone to read the ROM code. While researchers do have some idea what this code does by inferring the functions, there is no way to read and audit it. So the ME remains a black box for now.

3. The backdoor is active even when the machine is powered off:

Intel rolled out something horrible [hackaday.com]

The ME has network access, access to the host operating system, memory, and cryptography engine. The ME can be used remotely even if the PC is powered off. If that sounds scary, it gets even worse: no one knows what the ME is doing, and we can't even look at the code.

Blackhat 2017: How To Hack A Turned Off Computer Or Running Unsigned Code In Intel Management Engine [blackhat.com]

4. Onboard ethernet and WiFi is part of the backdoor:

The ME has its own MAC and IP address for the out-of-band interface, with direct access to the Ethernet controller; one portion of the Ethernet traffic is diverted to the ME even before reaching the host's operating system

If your CPU has Intel Anti-Theft Technology enabled, it is also possible to directly access the backdoor from cell towers using 3G.

5. The backdoor uses encrypted communication:

https://en.wikipedia.org/wiki/Intel_Active_Management_Technology#Using_Intel_AMT [wikipedia.org]

AMT version 4.0 and higher can establish a secure communication tunnel between a wired PC and an IT console outside the corporate firewall. In this scheme, a management presence server (Intel calls this a "vPro-enabled gateway") authenticates the PC, opens a secure TLS tunnel between the IT console and the PC

6. Recent backdoors run Java applets

*3 billion devices run Java* because everyone's motherboard is running it.

https://en.wikipedia.org/wiki/Intel_Active_Management_Technology [wikipedia.org]

Starting with ME 7.1, the ARC processor can also execute signed Java applets. The ME state is stored in a partition of the SPI flash, using the Embedded Flash File System.

7. Possible attack vectors from Intel/CIA/NSA (who holds the certificate):

Cross-Device Attack Vectors:
1. Obtain CA Cert trusted by ME > Broadcast DHCP announcement with domain name matching the certificate > Ethernet-Port > CPU backdoor (No exploits required, still works when system is turned off)

2. Insecure mobile > Broadcast wireless magic packet (CA cert broadcast) > On-Chip-Wifi/On-Chip-Intel-Wireless-Display > CPU backdoor (Only a backdoored mobile is required)

Other Attack Vectors:
3. Cell tower broadcast > Intel Anti-theft technology (On-Chip 3G receiver) > CPU backdoor

4. Zero day browser exploit > Powershell > Intel AMT > CPU backdoor

8. Backdoor inside a backdoor

For years Intel acted as if they weren't simply selling spy gears for the US government, but the Vault 7 leak forced them to come out in the open. On May 1st 2017, Intel released a "Critical" security bulletin INTEL-SA-00075 [intel.com], admitting Intel Core CPU from 1st gen to 7th gen (2006-2017) all share the same critical vulnerability:

CVE Name: CVE-2017-5689
Impact of vulnerability: Elevation of Privilege
Severity rating: Critical
Original release: May 01, 2017

There is an escalation of privilege vulnerability in Intel Active Management Technology (AMT), Intel Standard Manageability (ISM), and Intel Small Business Technology versions firmware versions 6.x, 7.x, 8.x 9.x, 10.x, 11.0, 11.5, and 11.6 that can allow an unprivileged attacker to gain control of the manageability features provided by these products.

Intel created a backdoor in the ME built-in web server authentication by using strncmp() to compare password, anyone sending an empty string as password with a length of 0 can get straight into the system, with no access log on both Intel ME and the OS:

Intel AMT vulnerability: Silent Bob is Silent [ycombinator.com]

The hijacking flaw that lurked in Intel chips is worse than anyone thought [arstechnica.com]

The bug was in the code to compare the two passwords. It used the strncmp function that compares the first N characters of two strings:
strncmp(string1, string2, N)

Sending an empty password, the compare code does this:
strncmp("6629fae49393a05397450978507c4ef1","",0)

Which is equivalent to:
strncmp("","",0)

And always return true.

Many vulnerable systems were found exposed to the internet:

The hijacking flaw that lurked in Intel chips is worse than anyone thought [arstechnica.com]

A query of the Shodan security search engine found over 8,500 systems with the AMT interface exposed to the Internet, with over 2,000 in the United States alone.

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