Re: Palladium -- trivially weak in hw but secure in software?? (Re: palladium presentation - anyone going?)
Software-based attacks are redistributable. Once I write a program that hacks a computer, I can give that program to anyone to use. I can even give it to everyone, and then anyone could use it. The expertise necessary can be abstracted away into a program even my mother could use. Hardware-based attacks cannot be redistributed. If I figure out how to hack my system, I can post instructions on the web but it still requires technical competence on your end if you want to hack your system too. While this doesn't help a whole lot for a DRM goal (once you get the non-DRM version of the media data, you can redistribute it all you want). I think this assumption may be incorrect. In order for content providers to win the DRM fight it seems like they need to address two issues. First, put up a big enough barrier for most users that circumventing access controls is infeasible, or simply not worth it. Second, put up a big enough barrier for most users that gaining access to copies of media with the access controls removed is either infeasible, or simply not worth it. I believe tamper resistant hardware solves the first problem, even if, as Adam conjectures, all that is required to access media protected by Palladium is a $50 kit (which remember, you can't obtain legally) and some hardware hacking. This seems to rule out well over %99 of the media consuming public. The problem of obstructing the distribution of media is really a different topic. I think that solving this problem is easier than most folks think. Again, you don't have to totally stop it P2P, or that kid in the shopping mall selling copied CD's. All you have to do is put up big enough technical and legal barriers that the general public would rather just pay for the media. While it may be the case that Palladium is not a serious barrier to the average CS graduate student, Cypherpunk, or even the home user who has a modicum of hardware clue, I don't think this will kill it as an effective technology for supporting DRM, assuming that the software cannot be broken. --Tal
Re: palladium presentation - anyone going?
On Sun, Oct 20, 2002 at 10:38:35PM -0400, Arnold G. Reinhold wrote: There may be a hole somewhere, but Microsoft is trying hard to get it right and Brian seemed quite competent. It doesn't sound breakable in pure software for the user, so this forces the user to use some hardware hacking. They disclaimed explicitly in the talk announce that: | Palladium is not designed to provide defenses against | hardware-based attacks that originate from someone in control of the | local machine. However I was interested to know exactly how easy it would be to defeat with simple hardware modifications or reconfiguration. You might ask why if there is no intent for Palladium to be secure against the local user, then why would the design it so that the local user has to use (simple) hardware attacks. Could they not, instead of just make these functions available with a user present test in the same way that the TOR and SCP functions can be configured by the user (but not by hostile software). For example why not a local user present function to lie about TOR hash to allow debugging (for example). Adam Back wrote: - isn't it quite weak as someone could send different information to the SCP and processor, thereby being able to forge remote attestation without having to tamper with the SCP; and hence being able to run different TOR, observe trusted agents etc. There is also a change to the PC memory management to support a trusted bit for memory segments. Programs not in trusted mode can't access trusted memory. A trusted bit in the segment register doesn't make it particularly hard to break if you have access to the hardware. For example you could: - replace your RAM with dual-ported video RAM (which can be read using alternate equipment on the 2nd port). - just keep RAM powered-up through a reboot so that you load a new TOR which lets you read the RAM. Also there will be three additional x86 instructions (in microcode) to support secure boot of the trusted kernel and present a SHA1 hash of the kernel code in a read only register. But how will the SCP know that the hash it reads comes from the processor (as opposed to being forged by the user)? Is there any authenticated communication between the processor and the SCP? Adam -- http://www.cypherspace.net/
Re: palladium presentation - anyone going?
At 10:52 PM +0100 10/21/02, Adam Back wrote: On Sun, Oct 20, 2002 at 10:38:35PM -0400, Arnold G. Reinhold wrote: There may be a hole somewhere, but Microsoft is trying hard to get it right and Brian seemed quite competent. It doesn't sound breakable in pure software for the user, so this forces the user to use some hardware hacking. They disclaimed explicitly in the talk announce that: | Palladium is not designed to provide defenses against | hardware-based attacks that originate from someone in control of the | local machine. However I was interested to know exactly how easy it would be to defeat with simple hardware modifications or reconfiguration. You might ask why if there is no intent for Palladium to be secure against the local user, then why would the design it so that the local user has to use (simple) hardware attacks. Could they not, instead of just make these functions available with a user present test in the same way that the TOR and SCP functions can be configured by the user (but not by hostile software). One of the services that Palladium offers, according to the talk announcement, is: b. Attestation. The ability for a piece of code to digitally sign or otherwise attest to a piece of data and further assure the signature recipient that the data was constructed by an unforgeable, cryptographically identified software stack. It seems to me such a service requires that Palladium be secure against the local user. I think that is the main goal of the product. For example why not a local user present function to lie about TOR hash to allow debugging (for example). Adam Back wrote: - isn't it quite weak as someone could send different information to the SCP and processor, thereby being able to forge remote attestation without having to tamper with the SCP; and hence being able to run different TOR, observe trusted agents etc. There is also a change to the PC memory management to support a trusted bit for memory segments. Programs not in trusted mode can't access trusted memory. A trusted bit in the segment register doesn't make it particularly hard to break if you have access to the hardware. For example you could: - replace your RAM with dual-ported video RAM (which can be read using alternate equipment on the 2nd port). - just keep RAM powered-up through a reboot so that you load a new TOR which lets you read the RAM. Brian mentioned that the system will not be secure against someone who can access the memory bus. But I can see steps being taken in the future to make that mechanically difficult. The history of the Scanner laws is instructive. Originally one had the right to listen to any radio communication as long as you did not make use of the information received. Then Congress banned the sale of scanners that can receive cell phone frequencies. Subsequently the laws were tightened to require scanners be designed so that their frequency range cannot be modified. In practice this means the control chip must be potted in epoxy. I can see similar steps being taken with Palladium PCs. Memory expansion could be dealt with by finding a way to give Palladium preferred access to the first block of physical memory that is soldered on the mother board. Also there will be three additional x86 instructions (in microcode) to support secure boot of the trusted kernel and present a SHA1 hash of the kernel code in a read only register. But how will the SCP know that the hash it reads comes from the processor (as opposed to being forged by the user)? Is there any authenticated communication between the processor and the SCP? Brian also mentioned that there would be changes to the Southbridge LCP bus, which I gather is a local I/O bus in PCs. SCP will sit on that and presumably the changes are to insure that the SCP can only be accessed in secure mode. At 12:27 AM +0100 10/22/02, Peter Clay wrote: I've been trying to figure out whether the following attack will be feasible in a Pd system, and what would have to be incorporated to prevent against it. Alice runs trusted application T on her computer. This is some sort of media application, which acts on encoded data streamed over the internet. Mallory persuades Alice to stream data which causes a buffer overrun in T. The malicious code, running with all of T's privileges: - abducts choice valuable data protected by T (e.g. individual book keys for ebooks) - builds its own vault with its own key - installs a modified version of T, V, in that vault with access to the valuable data - trashes T's vault The viral application V is then in an interesting position. Alice has two choices: - nuke V and lose all her data (possibly including all backups, depending on how backup of vaults works) - allow V to act freely There are two cases here. One is a buffer overflow in one of the trusted agents running in Palladium. Presumably an attack here will only be able to damage vaults associated with the product
Palladium -- trivially weak in hw but secure in software?? (Re: palladium presentation - anyone going?)
Remote attestation does indeed require Palladium to be secure against the local user. However my point is while they seem to have done a good job of providing software security for the remote attestation function, it seems at this point that hardware security is laughable. So they disclaim in the talk announce that Palladium is not intended to be secure against hardware attacks: | Palladium is not designed to provide defenses against | hardware-based attacks that originate from someone in control of the | local machine. so one can't criticise the implementation of their threat model -- it indeed isn't secure against hardware based attacks. But I'm questioning the validity of the threat model as a realistic and sensible balance of practical security defenses. Providing almost no hardware defenses while going to extra-ordinary efforts to provide top notch software defenses doesn't make sense if the machine owner is a threat. The remote attestation function clearly is defined from the view that the owner is a threat. Without specifics and some knowledge of hardware hacking we can't quantify, but I suspect that hacking it would be pretty easy. Perhaps no soldering, $50 equipment and simple instructions anyone could follow. more inline below... On Mon, Oct 21, 2002 at 09:36:09PM -0400, Arnold G. Reinhold wrote: [about improving palladium hw security...] Memory expansion could be dealt with by finding a way to give Palladium preferred access to the first block of physical memory that is soldered on the mother board. I think standard memory could be used. I can think of simple processor modifications that could fix this problem with hardware tamper resistance assurance to the level of having to tamper with .13 micron processor. The processor is something that could be epoxyied inside a cartridge for example (with the cartridge design processor + L2 cache housings as used by some Intel pentium class processors), though probably having to tamper with a modern processor is plenty hard enough to match software security given software complexity issues. Adam -- http://www.cypherspace.net/
Re: Palladium -- trivially weak in hw but secure in software?? (Re: palladium presentation - anyone going?)
On Tue, Oct 22, 2002 at 04:52:16PM +0100, Adam Back wrote: So they disclaim in the talk announce that Palladium is not intended to be secure against hardware attacks: | Palladium is not designed to provide defenses against | hardware-based attacks that originate from someone in control of the | local machine. so one can't criticise the implementation of their threat model -- it indeed isn't secure against hardware based attacks. But I'm questioning the validity of the threat model as a realistic and sensible balance of practical security defenses. Providing almost no hardware defenses while going to extra-ordinary efforts to provide top notch software defenses doesn't make sense if the machine owner is a threat. This depends. I would say this is an interesting threat model. It makes the attacks non-redistributable. Software-based attacks are redistributable. Once I write a program that hacks a computer, I can give that program to anyone to use. I can even give it to everyone, and then anyone could use it. The expertise necessary can be abstracted away into a program even my mother could use. Hardware-based attacks cannot be redistributed. If I figure out how to hack my system, I can post instructions on the web but it still requires techinical competence on your end if you want to hack your system too. While this doesn't help a whole lot for a DRM goal (once you get the non-DRM version of the media data, you can redistribute it all you want), it can be very useful for security. It can help to eliminate the 'script kiddie' style of attackers. Rick
Re: palladium presentation - anyone going?
Palladium sets up a separate trusted virtual computer inside the PC processor, with its own OS, called Nexus, and it own applications, called agents. Holy crap. So does this mean that MS Windows 2005 with Palladium operating will take about 15 minutes to boot up? Will Age of Empires 5 even be able to run with all that crap going? And after that, I guess we'll find a reason to run another virtual machine on top of the Palladium virtual machine, no? Guess I gotta go upgrade my hardware... From: Arnold G. Reinhold [EMAIL PROTECTED] To: Adam Back [EMAIL PROTECTED], Cypherpunks [EMAIL PROTECTED] CC: Cryptography [EMAIL PROTECTED], Adam Back [EMAIL PROTECTED], [EMAIL PROTECTED] Subject: Re: palladium presentation - anyone going? Date: Sun, 20 Oct 2002 22:38:35 -0400 At 7:15 PM +0100 10/17/02, Adam Back wrote: Would someone at MIT / in Boston area like to go to this [see end] and send a report to the list? I went. It was a good talk. The room was jam packed. Brian is very forthright and sincere. After he finished speaking, Richard Stallman gave an uninvited rebuttal speech, saying Palladium was very dangerous and ought to be banned. His concerns are legitimate, but the net effect, I think, was to make the QA session that followed less hostile. Palladium sets up a separate trusted virtual computer inside the PC processor, with its own OS, called Nexus, and it own applications, called agents. The trusted computer communicates with a security co-processor on the mother board, and has a secure channel to your keyboard and mouse and to a selected window on your CRT screen. How to prevent the secure channel to the on-screen window from being spoofed is still an open problem. Brian suggested a secure mode LED that lights when that window has focus or having the secure window display a mother's-maden-name type code word that you only tell Nexus. Of course this doesn't matter for DRM since *your* trusting the window is not the issue. All disk and network I/O is done thru the untrusted Windows OS on the theory that the trusted machine will encrypt anything it wants to keep private. Windows even takes care of Nexus scheduling. A major design goal is that all existing software must run without change. Users are not required to boot Palladium at all, and are to be able to boot it long after Windows has booted. Might help clear up some of the currently unexplained aspects about Palladium, such as: - why they think it couldn't be used to protect software copyright (as the subject of Lucky's patent) The specific question never came up. As Brain did say, Palladium is just a platform. People can built whatever they want on top of it. It seemed clear to me that the primary goal is DRM, but as someone else in the audience said (approximate quote) We always hear that you can't do this or that without trusted hardware. Well, this is trusted hardware. I don't see why anyone would think protecting software copyright could not be done. - are there plans to move SCP functions into processor? any relation to Intel Lagrange No. The SCP is based on a smart card core and is to be a light weight, low pin count chip with a target cost of $1 in volume. I presume future deals between MS and Intel are always possible. The SCP will support several algorithms, including 2048-bit RSA, 128-bit AES, SHA1, an HMAC. They may include another cipher and another hash. There will also be a FIPS140-2 Random Number Generator and several monotonic counters, but no time of day clock. Each chip will have a unique RSA key pair, an AES key and a HMAC key. The only key that the SCP will reveal to the outside is the RSA public key and it will only do that once per power up cycle. - isn't it quite weak as someone could send different information to the SCP and processor, thereby being able to forge remote attestation without having to tamper with the SCP; and hence being able to run different TOR, observe trusted agents etc. There is also a change to the PC memory management to support a trusted bit for memory segments. Programs not in trusted mode can't access trusted memory. Also there will be three additional x86 instructions (in microcode) to support secure boot of the trusted kernel and present a SHA1 hash of the kernel code in a read only register. There may be a hole somewhere, but Microsoft is trying hard to get it right and Brian seemed quite competent. I notice at the bottom of the talk invite it says | Palladium is not designed to provide defenses against | hardware-based attacks that originate from someone in control of the | local machine. but in this case how does it meet the BORA prevention. Is it BORA prevention _presuming_ the local user is not interested to reconfigure his own hardware? Near as I can see, the real trust comes from the RSA key pair stored in the SCP and a cert on that key from the SCP manufacturer. There is no command to obtain the private key
palladium presentation - anyone going?
Would someone at MIT / in Boston area like to go to this and send a report to the list? Might help clear up some of the currently unexplained aspects about Palladium, such as: - why they think it couldn't be used to protect software copyright (as the subject of Lucky's patent) - are there plans to move SCP functions into processor? any relation to Intel Lagrange - isn't it quite weak as someone could send different information to the SCP and processor, thereby being able to forge remote attestation without having to tamper with the SCP; and hence being able to run different TOR, observe trusted agents etc. I notice at the bottom of the talk invite it says | Palladium is not designed to provide defenses against | hardware-based attacks that originate from someone in control of the | local machine. but in this case how does it meet the BORA prevention. Is it BORA prevention _presuming_ the local user is not interested to reconfigure his own hardware? Will it really make any significant difference to DRM enforcement rates? Wouldn't the subset of the file sharing community who produce DVD rips still produce Pd DRM rips if the only protection is the assumption that the user won't make simple hardware modifications. Adam Original Message Subject: LCS/CIS Talk, OCT 18, TOMORROW Date: Thu, 17 Oct 2002 12:49:01 -0400 From: Be Blackburn [EMAIL PROTECTED] To: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] Open to the Public Date: Friday, Oct 18, 2002 Time: 10:30 a.m.- 12:00 noon Place:NOTE: NE43-518, 200 Tech Square Title:Palladium Speaker: Brian LaMacchia, Microsoft Corp. Hosts:Ron Rivest and Hal Abelson Abstract: This talk will present a technical overview of the Microsoft Palladium Initiative. The Palladium code name refers to a set of hardware and software security features currently under development for a future version of the Windows operating system. Palladium adds four categories of security services to today's PCs: a. Curtained memory. The ability to wall off and hide pages of main memory so that each Palladium application can be assured that it is not modified or observed by any other application or even the operating system. b. Attestation. The ability for a piece of code to digitally sign or otherwise attest to a piece of data and further assure the signature recipient that the data was constructed by an unforgeable, cryptographically identified software stack. c. Sealed storage. The ability to securely store information so that a Palladium application or module can mandate that the information be accessible only to itself or to a set of other trusted components that can be identified in a cryptographically secure manner. d. Secure input and output. A secure path from the keyboard and mouse to Palladium applications, and a secure path from Palladium applications to an identifiable region of the screen. Together, these features provide a parallel execution environment to the traditional kernel- and user-mode stacks. The goal of Palladium is to help protect software from software; that is, to provide a set of features and services that a software application can use to defend against malicious software also running on the machine (viruses running in the main operating system, keyboard sniffers, frame grabbers, etc). Palladium is not designed to provide defenses against hardware-based attacks that originate from someone in control of the local machine.
