TPM Boot Integrity

Assuring the integrity of a platform by demonstrating that the boot process starts from a trusted combination of hardware and software and continues until the operating system has fully booted and applications are running. Sometimes called Static Root of Trust Measurement (STRM).

ID: D3-TBI
Subclasses: 
Artifacts: 
Tactic:

Informational References

https://d3fend.mitre.org/technique/d3f:TPMBootIntegrity/

Countermeasures

ID Name Description NIST Rev5 D3FEND ISO 27001
CM0014 Secure boot Software/Firmware must verify a trust chain that extends through the hardware root of trust, boot loader, boot configuration file, and operating system image, in that order. The trusted boot/RoT computing module should be implemented on radiation tolerant burn-in (non-programmable) equipment.  AC-14 PL-8 PL-8(1) SA-8(10) SA-8(12) SA-8(13) SA-8(3) SA-8(30) SA-8(4) SC-51 SI-7 SI-7(1) SI-7(10) SI-7(9) D3-PH D3-BA D3-DLIC D3-TBI A.5.8

Related SPARTA Techniques and Sub-Techniques

ID Name Description
IA-0001 Compromise Supply Chain Threat actors may manipulate or compromise products or product delivery mechanisms before the customer receives them in order to achieve data or system compromise.
IA-0001.02 Software Supply Chain Threat actors may manipulate software binaries and applications prior to the customer receiving them in order to achieve data or system compromise. This attack can take place in a number of ways, including manipulation of source code, manipulation of the update and/or distribution mechanism, or replacing compiled versions with a malicious one.
IA-0002 Compromise Software Defined Radio Threat actors may target software defined radios due to their software nature to establish C2 channels. Since SDRs are programmable, when combined with supply chain or development environment attacks, SDRs provide a pathway to setup covert C2 channels for a threat actor.
IA-0004 Secondary/Backup Communication Channel Threat actors may compromise alternative communication pathways which may not be as protected as the primary pathway. Depending on implementation the contingency communication pathways/solutions may lack the same level of security (i.e., physical security, encryption, authentication, etc.) which if forced to use could provide a threat actor an opportunity to launch attacks. Typically these would have to be coupled with other denial of service techniques on the primary pathway to force usage of secondary pathways.
IA-0004.02 Receiver Threat actors may target the backup/secondary receiver on the space vehicle as a method to inject malicious communications into the mission. The secondary receivers may come from different supply chains than the primary which could have different level of security and weaknesses. Similar to the ground station, the communication through the secondary receiver could be forced or happening naturally.
IA-0007 Compromise Ground System Threat actors may initially compromise the ground system in order to access the target spacecraft. Once compromised, the threat actor can perform a multitude of initial access techniques, including replay, compromising FSW deployment, compromising encryption keys, and compromising authentication schemes. Threat actors may also perform further reconnaissance within the system to enumerate mission networks and gather information related to ground station logical topology, missions ran out of said ground station, birds that are in-band of targeted ground stations, and other mission system capabilities.
IA-0007.01 Compromise On-Orbit Update Threat actors may manipulate and modify on-orbit updates before they are sent to the target spacecraft. This attack can be done in a number of ways, including manipulation of source code, manipulating environment variables, on-board table/memory values, or replacing compiled versions with a malicious one.
EX-0004 Compromise Boot Memory Threat actors may manipulate boot memory in order to execute malicious code, bypass internal processes, or DoS the system. This technique can be used to perform other tactics such as Defense Evasion.
EX-0005 Exploit Hardware/Firmware Corruption Threat actors can target the underlying hardware and/or firmware using various TTPs that will be dependent on the specific hardware/firmware. Typically, software tools (e.g., antivirus, antimalware, intrusion detection) can protect a system from threat actors attempting to take advantage of those vulnerabilities to inject malicious code. However, there exist security gaps that cannot be closed by the above-mentioned software tools since they are not stationed on software applications, drivers or the operating system but rather on the hardware itself. Hardware components, like memory modules and caches, can be exploited under specific circumstances thus enabling backdoor access to potential threat actors. In addition to hardware, the firmware itself which often is thought to be software in its own right also provides an attack surface for threat actors. Firmware is programming that's written to a hardware device's non-volatile memory where the content is saved when a hardware device is turned off or loses its external power source. Firmware is written directly onto a piece of hardware during manufacturing and it is used to run on the device and can be thought of as the software that enables hardware to run. In the space vehicle context, firmware and field programmable gate array (FPGA)/application-specific integrated circuit (ASIC) logic/code is considered equivalent to firmware.
EX-0005.01 Design Flaws Threat actors may target design features/flaws with the hardware design to their advantage to cause the desired impact. Threat actors may utilize the inherent design of the hardware (e.g. hardware timers, hardware interrupts, memory cells), which is intended to provide reliability, to their advantage to degrade other aspects like availability. Additionally, field programmable gate array (FPGA)/application-specific integrated circuit (ASIC) logic can be exploited just like software code can be exploited. There could be logic/design flaws embedded in the hardware (i.e., FPGA/ASIC) which may be exploitable by a threat actor.
PER-0001 Memory Compromise Threat actors may manipulate memory (boot, RAM, etc.) in order for their malicious code and/or commands to remain on the victim spacecraft. The spacecraft may have mechanisms that allow for the automatic running of programs on system reboot, entering or returning to/from safe mode, or during specific events. Threat actors may target these specific memory locations in order to store their malicious code or file, ensuring that the attack remains on the system even after a reset.
PER-0002 Backdoor Threat actors may find and target various backdoors, or inject their own, within the victim spacecraft in the hopes of maintaining their attack.
PER-0002.02 Software Threat actors may inject code to create their own backdoor to establish persistent access to the spacecraft. This may be done through modification of code throughout the software supply chain or through modification of the software-defined radio configuration (if applicable).
DE-0007 Rootkit Rootkits are programs that hide the existence of malware by intercepting/hooking and modifying operating system API calls that supply system information. Rootkits or rootkit enabling functionality may reside at the flight software or kernel level in the operating system or lower, to include a hypervisor, Master Boot Record, or System Firmware.
DE-0008 Bootkit Adversaries may use bootkits to persist on systems and evade detection. Bootkits reside at a layer below the operating system and may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly.
EXF-0006 Modify Communications Configuration Threat actors can manipulate communications equipment, modifying the existing software, hardware, or the transponder configuration to exfiltrate data via unintentional channels the mission has no control over.
EXF-0006.01 Software Defined Radio Threat actors may target software defined radios due to their software nature to setup exfiltration channels. Since SDRs are programmable, when combined with supply chain or development environment attacks, SDRs provide a pathway to setup covert exfiltration channels for a threat actor.
EXF-0006.02 Transponder Threat actors may change the transponder configuration to exfiltrate data via radio access to an attacker-controlled asset.

Space Threats Mapped

ID Description
SV-CF-2 Eavesdropping (RF and proximity)
SV-IT-2 Unauthorized modification or corruption of data
SV-MA-3 Attacks on critical software subsystems
Attitude Determination and Control (AD&C) subsystem determines and controls the orientation of the satellite. Any cyberattack that could disrupt some portion of the control loop - sensor data, computation of control commands, and receipt of the commands would impact operations
Telemetry, Tracking and Commanding (TT&C) subsystem provides interface between satellite and ground system. Computations occur within the RF portion of the TT&C subsystem, presenting cyberattack vector
Command and Data Handling (C&DH) subsystem is the brains of the satellite. It interfaces with other subsystems, the payload, and the ground. It receives, validate, decodes, and sends commands to other subsystems, and it receives, processes, formats, and routes data for both the ground and onboard computer. C&DH has the most cyber content and is likely the biggest target for cyberattack.
Electrical Power Subsystem (EPS) provides, stores, distributes, and controls power on the satellite. An attack on EPS could disrupt, damage, or destroy the satellite.
SV-SP-1 Exploitation of software vulnerabilities (bugs); Unsecure code, logic errors, etc. in the FSW.
SV-SP-3 Introduction of malicious software such as a virus, worm, Distributed Denial-Of-Service (DDOS) agent, keylogger, rootkit, or Trojan Horse
SV-SP-6 Software reuse, COTS dependence, and standardization of onboard systems using building block approach with addition of open-source technology leads to supply chain threat
SV-SP-9 On-orbit software updates/upgrades/patches/direct memory writes. If TT&C is compromised or MOC or even the developer's environment, the risk exists to do a variation of a supply chain attack where after it is in orbit you inject malicious code
SV-AC-6 Three main parts of S/C. CPU, memory, I/O interfaces with parallel and/or serial ports. These are connected via busses (i.e., 1553) and need segregated. Supply chain attack on CPU (FPGA/ASICs), supply chain attack to get malware burned into memory through the development process, and rogue RTs on 1553 bus via hosted payloads are all threats. Security or fault management being disabled by non-mission critical or payload; fault injection or MiTM into the 1553 Bus - China has developed fault injector for 1553 - this could be a hosted payload attack if payload has access to main 1553 bus; One piece of FSW affecting another. Things are not containerized from the OS or FSW perspective;
SV-AC-8 Malicious Use of hardware commands - backdoors / critical commands
SV-IT-3 Compromise boot memory
SV-SP-11 Software defined radios - SDR is also another computer, networked to other parts of the spacecraft that could be pivoted to by an attacker and infected with malicious code. Once access to an SDR is gained, the attacker could alter what the SDR thinks is correct frequencies and settings to communicate with the ground.
SV-SP-7 Software can be broken down into three levels (operating system and drivers’ layer, data handling service layer, and the application layer). Highest impact on system is likely the embedded code at the BIOS, kernel/firmware level. Attacking the on-board operating systems. Since it manages all the programs and applications on the computer, it has a critical role in the overall security of the system. Since threats may occur deliberately or due to human error, malicious programs or persons, or existing system vulnerability mitigations must be deployed to protect the OS.
SV-AV-6 Complete compromise or corruption of running state
SV-DCO-1 Not knowing that you were attacked, or attack was attempted
SV-AC-1 Attempting access to an access-controlled system resulting in unauthorized access
SV-IT-1 Communications system spoofing resulting in denial of service and loss of availability and data integrity
SV-AC-7 Weak communication protocols. Ones that don't have strong encryption within it
SV-MA-7 Exploit ground system and use to maliciously to interact with the spacecraft
SV-MA-6 Not planning for security on SV or designing in security from the beginning
SV-SP-4 General supply chain interruption or manipulation

Sample Requirements

Requirement
The spacecraft shall protect the confidentiality and integrity of the [all information] using cryptography while it is at rest. {SV-IT-2,SV-CF-2} {SC-28,SC-28(1),SI-7(6)}
The Program shall define processes and procedures to be followed when the integrity verification tools detect unauthorized changes to [Program-defined software, firmware, and information]. {SV-IT-2} {SI-7}
The Program shall enable integrity verification of software and firmware components. {SV-IT-2} {SA-10(1),SI-7}
The spacecraft shall perform an integrity check of [Program-defined software, firmware, and information] at startup; at [Program-defined transitional states or security-relevant events] {SV-IT-2} {SI-7(1)}
The Program shall define and document the transitional state or security-relevant events when the spacecraft will perform integrity checks on software, firmware, and information. {SV-IT-2} {SI-7(1)}
The spacecraft shall provide automatic notification to [Program-defined personnel (e.g., ground operators)] upon discovering discrepancies during integrity verification. {SV-IT-2} {SI-7(2)}
The Program shall employ automated tools that provide notification to [Program-defined personnel] upon discovering discrepancies during integrity verification. {SV-IT-2} {SI-7(2)}
The Program shall define the security safeguards that are to be employed when integrity violations are discovered. {SV-IT-2} {SI-7(5)}
The spacecraft shall automatically [Selection (one or more):restarts the FSW/processor, performs side swap, audits failure; implements Program-defined security safeguards] when integrity violations are discovered. {SV-IT-2} {SI-7(8)}
The Program shall maintain a list of suppliers and potential suppliers used, and the products that they supply to include software. {SV-SP-3,SV-SP-4,SV-SP-11} {PL-8(2)}
The spacecraft shall perform attestation at each stage of startup and ensure overall trusted boot regime (i.e., root of trust). {SV-IT-3} {SI-7(9)}
The trusted boot/RoT shall be a separate compute engine controlling the trusted computing platform cryptographic processor. {SV-IT-3} {SI-7(9)}
The trusted boot/RoT computing module shall be implemented on radiation tolerant burn-in (non-programmable) equipment. {SV-IT-3} {SI-7(9)}
The spacecraft boot firmware must verify a trust chain that extends through the hardware root of trust, boot loader, boot configuration file, and operating system image, in that order. {SV-IT-3} {SI-7(9)}
The spacecraft boot firmware must enter a recovery routine upon failing to verify signed data in the trust chain, and not execute or trust that signed data. {SV-IT-3} {SI-7(9)}
The spacecraft shall allocate enough boot ROM memory for secure boot firmware execution. {SV-IT-3} {SI-7(9)}
The spacecraft shall allocate enough SRAM memory for secure boot firmware execution. {SV-IT-3} {SI-7(9)}
The spacecraft secure boot mechanism shall be Commercial National Security Algorithm Suite (CNSA) compliant. {SV-IT-3} {SI-7(9)}
The spacecraft shall support the algorithmic construct Elliptic Curve Digital Signature Algorithm (ECDSA) NIST P-384 + SHA-38{SV-IT-3} {SI-7(9)}
The spacecraft hardware root of trust must be an ECDSA NIST P-384 public key. {SV-IT-3} {SI-7(9)}
The spacecraft hardware root of trust must be loadable only once, post-purchase. {SV-IT-3} {SI-7(9)}
The spacecraft boot firmware must validate the boot loader, boot configuration file, and operating system image, in that order, against their respective signatures. {SV-IT-3} {SI-7(9)}
The spacecraft, upon detection of a potential integrity violation, shall provide the capability to [audit the event and alert ground operators]. {SV-DCO-1} {SI-7(8)}
The spacecraft shall implement cryptographic mechanisms to prevent unauthorized disclosure of, and detect changes to, information during transmission unless otherwise protected by alternative physical safeguards. {SV-AC-7} {SC-8(1),SI-7(6)}
The Program shall document and design a security architecture using a defense-in-depth approach that allocates the Program defined safeguards to the indicated locations and layers: [Examples include operating system abstractions and hardware mechanisms to the separate processors in the spacecraft, internal components, and the FSW]. {SV-MA-6} {PL-8,PL-8(1)}
The Program shall ensure that the allocated security safeguards operate in a coordinated and mutually reinforcing manner. {SV-MA-6} {PL-8(1)}