Securing Computer Hardware Using Tpm

¶ … Trusted Platform Module is a dedicated microprocessor that is designed to secure computer hardware. TPM secures hardware by integrating cryptographic keys into the computer devices. According to Potter (2009)

the cryptographic keys are specific to the host system and they are used for authenticating the host systems hardware. Using hardware-based cryptography will ensure that all the information stored in the hardware is protected from any external software attacks. TPM security is vital to ensure that threats that occur at the hardware level are detected, and prevented from spreading to other computers. Hardware level threats target the BIOS system. When the computer BIOS has been attacked no software antivirus will have the capability to recognize the attack. TPM will authenticate the hardware in the system to provide platform integrity. Platform integrity will measure the integrity of the boot sector, disk MBR, BIOS, and operating system. The integrity measurement is intended to ensure that no unauthorized changes have taken place. If changes are detected, integrity test will fail, and the system will not fail to boot. TPM has the capability to recover and boot from the last known good configuration.

TPM is able to prevent malware attacks and rootkit attacks. Platform integrity will detect if there are any malware or rootkit attacks and this will prevent the computer form booting up. Preventing the system from booting will ensure that the user's data and information is secure. Platform integrity will ensure that before a computer is allowed network access it has to pass the integrity measurement. Authenticating users in a network is harder nowadays since attackers have discovered ways of cloning computers within a network. Using TPM the network administrator is able to identity, and confirm the identity of all the computers on the network before they authorize the computers to access the network. Ensuring that only healthy computers have access to the network will prevent the spread of viruses or malware. The number of black hat attacks that have the capability to cause serious threats on hardware protected using TPM are fewer than those that can break encryption software. This indicates that TPM security offers a better level of security that any software-based tool currently available.

TPM chips provide for disk encryption. Disk encryption protects the contents of the disk from unauthorized users. The security provided by TCM is able to encrypt the entire disk volume or only the operating system volume. Disk encryption will prevent changes from taking place without the user's authorization. This will also protect any critical and sensitive information that the user might have stored on their computer Stefan, Wu, Yao, & Xu, 2009.

The encryption provided by TPM is self encrypting, which guards and secure the data in case the machine or drive is lost. The keys for encryption are stored in the drive. This increases security as there is no way an attacker will manage to gain access to the drive contents without the decryption keys. Storing the encryption keys in the drive also boost security, as the drive will independently authenticate the user. Independent authentication is not linked to the operating system, which ensures that drive contents cannot be accessed even if a person manages to override the operating system security.

TPM provides for increased password protection. The module has prevention mechanism that is built in and will protect against automated dictionary attacks. Dictionary attacks are used to guess a password by using words from a dictionary. The system will prevent automated attacks, but will provide the user will a reasonable number of tries before it locks them out. This level of protection enables user to specify shorter or weaker passwords that are more memorable. Using software only to prevent such an attack would result in easy access to hackers and attackers. This is because software is more prone to these attacks than hardware.

Trusted Platform Module authorization protocols

There are two main authorization protocols used by TPM namely Object Independent Authorization Protocol, and Object Specific Authorization Protocol. OIAP will create a session that will manipulate any object, but will only work with certain commands. OSAP will create a session that manipulates only a specific object when the objects session is set up. OIAP will open one authorization session, and during that session the same command could be issued many times. Once a session is open it is possible for that session to be used for the manipulation of other objects. The object could be independent of the initial session object. The only limitation of this protocol is the commands that can be used. There are commands like TPM_CreateWrapKey that cannot be used in the protocol. This command introduced a new authorization data to the TPM. Authorization occurs with each command that is exchanged between the different objects. For an object to gain access and execute a protected command, it has to correctly perform the required steps and submit the desired authorization data with each command it submits. The open session allows an object to avoid resubmitting the authorization session request, but it also makes the protocol prone to attackers. The attacker would place themselves between the object and TPM where he/she would be able to intercept the messages been sent. Once the object has opened an authorized session and submitted a request, the attacker could intercept the message and attach his/her own message. This would result in an error on the objects side, and they would have to open a new session leaving the old session still open. The attacker would use the open session to access secure information and the TPM would not realize they are not authorized. Bruschi, Cavallaro, Lanzi, and Monga (2005)

posits that OIAP is also prone to replaying a message, Denial of Service, and Man-in-The-Middle attacks. An attacker has the capability to deny services to authorized users. The attacker will block users from accessing messages sent by the TPM objects.