Hot answers tagged trusted-computing
13
Generally one has to know what TPMs and TXT and all these technologies are aimed to protect from, because there are misunderstandings.
TPMs, generally, enable 5 distinct processes, and only those:
Integrity measurement – computation of a cryptographic hash of a platform component
Authenticated boot – a process by which a platform's state (the sum of its ...
9
HTTPS (i.e. SSL/TLS) encrypts all HTTP communication including the entire URL. HTTPS does not protect the domain name as this is sent to the DNS in the clear, but it does protect the rest of the URL. Other apps don't have access to your app's SSL/TLS encrypted traffic including URLs. So as long as the SSL/TLS connection is setup securely an attacker won't be ...
8
You don't. Some vendors do indeed ship backdoors with their products, and many computers come with "crapware" pre-installed as a source of revenue for the manufacturers. Even apps that don't contain a backdoor can cause other damage (e.g. Browser toolbars that track browsing).
Same concerns apply with hardware, especially in networking equipment.
What you ...
7
Matthew Garrett has some nice blog posts on UEFI Secure Boot. Concerning your question he writes:
Anyone can pay $99 and get their binaries signed. So why won't malware authors just do that? For starters, you'll need to provide some form of plausible ID for Verisign to authenticate you and hand over access. So, sure, you provide some sort of fake ID. ...
6
Trusted Execution Technology is coupled with a collection of security features available on the modern Intel chipset. The Trusted Platform Module (TPM) and other DRM like features are also in this bundle. The reasoning behind this is because of abstraction, which is more commonly attributed to a software architecture. The commonality behind all of these ...
6
The Storage Root Key (SRK) is used to wrap TPM protected keys which can be stored outside the TPM. That data stored outside the TPM can be decrypted by passing it back through the TPM again for a decryption operation.
Keys wrapped by the SRK can themselves be used to wrap other keys, too. This method of wrapping can be used to create a key hierarchy of ...
5
Disclaimer: I'm not a TPM expert - most of this has come from a half hour's worth of research. I've managed to cobble together a reasonable understanding of the process and details from the TCG TPM spec, the TPM API documentation on MSDN, and various papers on the subject.
The SRK is an RSA key pair (of at least 2048-bit size) that is used as the root for ...
5
All the relevant tools are available for Linux, likely even more than elsewhere.
Much the open source spirit, you have to build everything yourself.
A free version of MS Bitlocker is suggested if you google "IBM blueprint eCryptFS TPM". Trousers also supports a PKCS#11 interface that allows integration with, e.g., Firefox. With Linux IMA, you get a nice ...
5
From Joanna Rutkowska's blog: (and I admit I'm skating at the edge of my understanding here...)
When you load a hypervisor using TXT, the SENTER instruction would first apply the VT-d protections around the hypervsior image, then do the measurements, and only then load it, with VT-d protections still in-place.
And her more complete explanation:
...
4
Try tpm-luks [1], which is a script that will assist in storing a new secret both in the TPM's NVRAM and a LUKS key slot.
This should do the trick:
$ tpm-luks -c -d <device>
You can find your LUKS device with:
# blkid -t TYPE=crypto_LUKS
I released tpm-luks very recently, so its only available in git ATM.
[1] ...
4
From what I know, nothing prevent this in practice, but the code was not written yet. You can take a look however on http://publib.boulder.ibm.com/infocenter/lnxinfo/v3r0m0/index.jsp?topic=%2Fliaai%2Fecrypts%2Fliaaiecryptfs.htm
The idea is use tpm_sealdata to encrypt a file, and then this can be unlocked only if the boot was not fiddled with.
You may ...
4
The TCG Trusted Computing concept devices the BIOS into two parts. The initial BIOS is assumed to be secure and will initialize the TPM. This so-called CRTM will then measure the remaining BIOS components and log their values in the TPM. From the spec it appears that CMOS data is part of that measurement and is stored to PCR1. But since a changed BIOS ...
4
A well designed TPM should be pretty resilient to tampering, but a truly determined attacker could try doing something like dissolving the casing and reading information directly off the chip. It's a pain staking and highly technical process, so probably isn't a likely case in most situations, but if the value of the material is known to be high enough, it ...
4
You don't. Most of the alleged backdoors have been software problems (Google for _NSAKEY, or Digital Encryption Standard and NSA interference, or Huawei and back doors), but a hardware backdoor isn't out of the question. The issue of concealing "intellectual privacy" or other concerns in proprietary software or hardware make this problem worse.
If all ...
4
When a TPM provides a remote attestation, several components are involved:
the TPM as a tamper-resistant device containing a root of trust;
the TPM as a device to measure the software running on the main processor and produce an attestation;
software to connect to the TPM and retrieve the attestation and transmit it (this software is merely relaying a ...
4
The TPM doesn't stop the boot. The boot will still continue, but the PCRs will have a different value in them than they used to (since now the BIOS is different than it was before). As a result, the system will be unable to unseal the sealed data. Of course, if the bootloader or kernel is unable to unseal the sealed partition, depending on how it is ...
4
Yes.
You can see both functions as being really two separate things, i.e., DRTM (Dynamic Root of Trust for Measurement) is just another way to extend PCR values (17-22) (like SRTM) while Remote Attestation will take whatever PCR you which to use (much like the SEAL operation). There’s no dependency or real link between those functionalities.
If you want ...
3
Does "dynamic chain of trust" support remote attestation?
When a dynamic launch is used on an area of memory, specific PCR indexes in the TPM are used to used to record the state of that software. If these PCR indexes are included in the attestation request by the challenger, then that software would be attested to in the response. These PCR indexes are ...
3
Many TPMs will allow a backup to be stored of the key either prior to loading it on to the TPM or via some kind of export. As long as you have the key, you can reload it on a new TPM if the TPM fries.
I actually had this exact thing happen with an IBM ThinkPad with an early TPM where the TPM circuit fried and I had to replace the system board. I was ...
3
Real security enhancements are created if you are buying for a commercial or governmental enterprise but at a cost related to supportability. For the majority of home users who want nothing more than a Microsoft desktop and never modify their purchased system it will also provided added security. For the home user that wants to dual boot (a very small ...
2
In an HTTPS connection the URL data is encrypted. The IP address and port of the server being connected to can be easily enumerated using a packet sniffer, so chances are if the URL can be sniffed the server isn't going to be a secret. Data transmitted within a https (ie SSL/TLS) connection is secret as long as there is no Man in the Middle, see previous ...
2
Set up an ad-hoc network on a computer.
Make your phone connect to the newly created network
Use Wireshark to see what connections are made
2
The safety of the TPM storage is based on two factors:
There is no hardware API for retrieving the private keys.
Under no circumstances will the key be transmitted to the host
Tamper-resistent hardware.
Countermeasures such as permanently sealing the chip in resin help prevent physical hacking. In most cases, there is a high probability that you will break ...
2
Secure Boot for PCs is inflexible and leaves you with few options if your system is somehow broken. It is also not designed to scale in an environment with multiple stakeholders - say your company wants to use Secure Boot to ensure not only a proper windows installation but also a set of certain policy-enforcing tools. Not possible out of the box.
Trusted ...
2
--- this is comment, not an answer ---
http://www.intel.com/design/mobile/platform/downloads/Trusted_Platform_Module_White_Paper.pdf
BIOS Code
The TCPA specifies the measurement of integrity of BIOS code at system startup. In order to accomplish such integrity measurement and reporting, the system BIOS has to be enhanced with integrity measurement ...
2
VT-d is simply Intel’s term to describe their IOMMU. AMD call it AMD-Vi. The role of this unit is to control Device Memory Access (DMA) and interrupt remapping.
Basically, VT-d provides some important aspect of isolation. The best way I have to describe it is by using a PCI passthrough example. Here’s my –simplistic – explanation:
If you dedicate a ...
2
However, it make me wonder... if the motherboard crashes, is the data lost forever?
That depends, primarily on whether the TPM is the only storage unit for the key. TPM units contain a SEAL command, TPM_SEAL, which can be used to verify the state of the system matches that stored in the TPM before the key will be released.
However, if the key is only ...
2
A virtualised environment could would be easier to handle in this case.
Firstly, in order to load any operating system, you need to emulate boot. So a VM implementation such as Intel VT only implements CPU emulation; the rest is up to the vm software. Everything must either be emulated or passed through with hardware support.
Boot is no exception - and as ...
1
This is more feedback than an answer. My apologies if I'm in the wrong area here.
There are several security baseline management tools out there for tablets, just fire up ye'ole Googlez. On the whole sand-boxing the devices seems to be the predominate approach, sadly. If you're interested in MS devices (masochism maybe?) this ( ...
1
There are many ways of using trusted computing. Depending on use would depend on what attacks apply, so far I know of TPM reset attacks which find some way to glitch the TPM chip to reset, sometimes requiring physical access to the processor: http://www.cs.dartmouth.edu/~pkilab/sparks/
Also there is was a talk at Blackhat DC in 2009 about a method to bypass ...
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