Lesson 12 Flashcards
Hardware root of Trust
•Hardware root of trust/trust anchor •Attestation •Trusted Platform Module (TPM) •Hardware-based storage of cryptographic data •Endorsement key •Subkeys used in key storage, signature, and encryption operations •Ownership secured
Hardware Root of Trust or Trust Anchor
A hardware Root of Trust (RoT) or trust anchor is a secure subsystem that is able to provide attestation.
Attestation means that a statement made by the system can be trusted by the receiver.
For example, when a computer joins a network, it might submit a report to the network access control (NAC) server declaring, "My operating system files have not been replaced with malicious versions." The hardware root of trust is used to scan the boot metrics and OS files to verify their signatures, then it signs the report. The NAC server can trust the signature and therefore the report contents if it can trust that the signing entity's private key is secure.
Attestation
(Hardware RoT provides this)
Attestation means that a statement made by the system can be trusted by the receiver.
For example, when a computer joins a network, it might submit a report to the network access control (NAC) server declaring, "My operating system files have not been replaced with malicious versions." The hardware root of trust is used to scan the boot metrics and OS files to verify their signatures, then it signs the report. The NAC server can trust the signature and therefore the report contents if it can trust that the signing entity's private key is secure
Trusted Platform Module (TPM)
- Hardware-based storage of cryptographic data
- Endorsement key
- Subkeys used in key storage, signature, and encryption operations
- Ownership secured via password
The RoT is usually established by a type of cryptoprocessor called a trusted platform
module (TPM). TPM is a specification for hardware-based storage of encryption keys,
hashed passwords, and other user and platform identification information. The TPM is
implemented either as part of the chipset or as an embedded function of the CPU.
Each TPM is hard-coded with a unique, unchangeable asymmetric private key calledthe endorsement key. This endorsement key is used to create various other typesof subkeys used in key storage, signature, and encryption operations. The TPM alsosupports the concept of an owner, usually identified by a password (though this isnot mandatory). Anyone with administrative control over the setup program can take
ownership of the TPM, which destroys and then regenerates its subkeys. A TPM canbe managed in Windows via the tpm.msc console or through group policy. On anenterprise network, provisioning keys to the TPM might be centrally managed via theKey Management Interoperability Protocol (KMIP).
Boot Integrity
- Unified extensible firmware interface (UEFI)
- Secure boot
* Validate digital signatures before running boot loader or OS kernel - Measured boot
* Use TPM to measure hashes of boot files at each stage - Boot Attestatio Attestation
- Report boot metrics and signatures to remote server
•Unified extensible firmware interface (UEFI)
(supports boot integrity) Most PCs and smartphones implement the unified extensible firmware interface
(UEFI). UEFI provides code that allows the host to boot to an OS. UEFI can enforce a number of boot integrity checks.
Secure Boot
- Secure boot
* Validate digital signatures before running boot loader or OS kernel (requires UEFI but not TPM)
Secure boot is designed to prevent a computer from being hijacked by a malicious OS.
UEFI is configured with digital certificates from valid OS vendors. The system firmware
checks the operating system boot loader and kernel using the stored certificate to
ensure that it has been digitally signed by the OS vendor. This prevents a boot loader
or kernel that has been changed by malware (or an OS installed without authorization)
from being used. Secure boot is supported on Windows and many linux platforms
Measured boot
- Measured boot
* Use TPM to measure hashes of boot files at each stage
A trusted or measured boot process uses platform configuration registers (PCRs)
in the TPM at each stage in the boot process to check whether hashes of key system state data (boot firmware, boot loader, OS kernel, and critical drivers) have changed
.This does not usually prevent boot, but it will record the presence of unsigned kernellevel
code.
Boot Attestation
- Boot Attestatio Attestation
- Report boot metrics and signatures to remote server
Boot attestation is the capability to transmit a boot log report signed by the TPM via a
trusted process to a remote server, such as a network access control server. The boot
log can be analyzed for signs of compromise, such as the presence of unsigned drivers.
The host can be prevented from accessing the network if it does not meet the required
health policy or if no attestation report is received.
Drive (disk) encryption
Drive Encryption
•Full disk encryption (FDE)
•Encryption key secured with user password
•Secure storage for key in TPM or USB thumb drive
- Self-encrypting drives (SED)
- Data/media encryption key (DEK/MEK)
- Authentication key (AK) or key encrypting key (KEK)
- Opal specification compliant
Full disk encryption (FDE)
- Full disk encryption (FDE)
- Encryption key secured with user password
- Secure storage for key in TPM or USB thumb drive
Full disk encryption (FDE) means that the entire contents of the drive (or volume), including system files and folders, are encrypted. OS ACL-based security measuresare quite simple to circumvent if an adversary can attach the drive to a different host
OS. Drive encryption allays this security concern by making the contents of the drive
accessible only in combination with the correct encryption key. Disk encryption can be
applied to both hard disk drives (HDDs) and solid state drives (SSDs).
FDE requires the secure storage of the key used to encrypt the drive contents.
Normally, this is stored in a TPM. The TPM chip has a secure storage area that a disk
encryption program, such as Windows BitLocker, can write its keys to. It is also possible
to use a removable USB drive (if USB is a boot device option). As part of the setup
process, you create a recovery password or key. This can be used if the disk is moved
to another computer or the TPM is damaged.
Self-encrypting drives (SED)
- Self-encrypting drives (SED)
- Data/media encryption key (DEK/MEK)
- Authentication key (AK) or key encrypting key (KEK)
- Opal specification compliant
One of the drawbacks of FDE is that, because the OS performs the cryptographic
operations, performance is reduced. This issue is mitigated by self-encrypting drives
(SED), where the cryptographic operations are performed by the drive controller. The
SED uses a symmetric data/media encryption key (DEK/MEK) for bulk encryption and
stores the DEK securely by encrypting it with an asymmetric key pair called either the
authentication key (AK) or key encryption key (KEK). Use of the AK is authenticated by
the user password. This means that the user password can be changed without having
to decrypt and re-encrypt the drive. Early types of SEDs used proprietary mechanisms,
but many vendors now develop to the Opal Storage Specification
Data/media encryption key (DEK/MEK) [for SED)
SED uses a symmetric data/media encryption key (DEK/MEK) for bulk encryption and
stores the DEK securely by encrypting it with an asymmetric key pair called either the
authentication key (AK) or key encryption key (KEK).
Authentication key (AK) or key encrypting key (KEK)
SED uses a symmetric data/media encryption key (DEK/MEK) for bulk encryption and
stores the DEK securely by encrypting it with an asymmetric key pair called either the
authentication key (AK) or key encryption key (KEK). Use of the AK is authenticated by
the user password.
USB and flash drie security
- BadUSB
- Exposes potential of malicious firmware
- Malicious USB cabl
- Malicious flash drive
- Sheep dip
- Sandbox system for testing new/suspect devices
- Isolated from production network/data
Bad USB
- BadUSB
- Exposes potential of malicious firmware
- Malicious USB cabl
- Malicious flash drive
As revealed by researcher Karsten Nohl in his BadUSB paper, exploiting the firmware of external
storage devices, such as USB flash drives (and potentially any other type of firmware),
presents adversaries with an incredible toolkit. The firmware can be reprogrammed
to make the device look like another device class, such as a keyboard. In this case it
could then be used to inject a series of keystrokes upon an attachment or work as
a keylogger. The device could also be programmed to act like a network device and
corrupt name resolution, redirecting the user to malicious websites.
Sheep dip
- Sheep dip
- Sandbox system for testing new/suspect devices
- Isolated from production network/data
A modified device may have visual clues that distinguish it from a mass manufactured
thumb drive or cable, but these may be difficult to spot. You should warn users of the
risks and repeat the advice to never attach devices of unknown provenance to their
computers and smartphones. If you suspect a device as an attack vector, observe a
sandboxed lab system (sometimes referred to as a sheep dip) closely when attaching the device
Third-party Risk Management
- Supply chain and vendors
- End-to-end process of supplying, manufacturing, distributing, and finally releasing goods and services to a customer
- Could malicious actors within supply chain introduce backdoor access via hardware/firmware components?
- Most companies must depend on governments/security services to ensure trustworthiness of market suppliers
- Consider implications of using second-hand equipment
- Vendors versus business partners
•Vendors versus business partners
When assessing suppliers for risk, it is helpful to distinguish two types of relationship:
• Vendor—this means a supplier of commodity goods and services, possibly with
some level of customization and direct support.
• Business partner—this implies a closer relationship where two companies share
quite closely aligned goals and marketing opportunities.
End of Life Systems and Lack of Vendor Support
- Support lifecycles
- End of life (EOL)
- Product is no longer sold to new customers
- Availability of spares and updates is reduced
- End of service life (EOSL)
- Product is no longer supported
- Lack of vendor support
- Abandonware
- Software and peripherals/devices
•End of life (EOL)
- Product is no longer sold to new customers
* Availability of spares and updates is reduced
•End of service life (EOSL)
•Product is no longer supported
•Lack of vendor support
- Abandonware
* Software and peripherals/devices
MOU
Intent to work together
Business partnership agreement (BPA)
Establish a formal partner relationship
Non-disclosure agreement (NDA)
Govern use and storage of shared confidential and private information
Service level agreement (SLA)
Establish metrics for service delivery and performance
Measurement systems analysis (MSA)
Evaluate data collection and statistical methods used for quality management
Host Hardening
- Reducing attack surface
- Interfaces
- Network and peripheralconnections and hardware ports
- Services
- Software that allows client connections
- Application service ports
- TCP and UDP ports
- Disable applicationservice or use firewall to control access
- Detect non-standard usage
- Encryption for persistent storage
least functionality (attack surface)
The essential principle is of least functionality;
that a system should run only the protocols and services required by legitimate users
and no more. This reduces the potential attack surface.
Interfaces (hardening)
Network and peripheralconnections and hardware ports
Interfaces provide a connection to the network. Some machines may have more than one interface.
***if any of these interfaces are not required, they should be explicitly disabled
rather than simply left unused.
Services (hardening)
Software that allows client connections
Services provide a library of functions for different types of applications. Some
services support local features of the OS and installed applications. Other services
support remote connections from clients to server applications.
***Unused services
should be disabled.
Application service ports
- Application service ports
- TCP and UDP ports
- Disable applicationservice or use firewall to control
allow client software to connect to applications over a
network. These should either be disabled or blocked at a firewall if remote access
is not required
Encryption for persistent storage
Persistent storage holds user data generated by applications, plus cached
credentials. Disk encryption is essential to data security. Self encrypting drives can
be used so that all data-at-rest is always stored securely.
Baseline Configuration and Registry Settings
You will have separate configuration baselines for desktop clients, file and print
servers, Domain Name System (DNS) servers, application servers, directory services
servers, and other types of systems.
- OS/host role
- Networkappliance, server, client, …
- Configuration baseline template
- Registry settings and group policy objects (GPOs)
- Malicious registry changes
- Baseline deviation reporting
•Registry settings and group policy objects (GPOs)
In Windows, configuration settings are stored in
the registry.
On a Windows domain network, each domain-joined computer will receive
policy settings from one or more group policy objects (GPOs).
- Malicious registry changes
* Baseline deviation reporting
just need to repeat this as part of Baseline Configuration and Registry Settings
Patch update poliicies and schedule
- Update policies and schedule
- Apply all latest –auto-update (used for SOHO)
- Only apply specific patches
- Third-party patches