Freedom to Tinker

How about another incident in 2022? Attackers BGP hijacked a dependency hosting a JS file, generated a rogue TLS certificate, and stole $2 million. Keep in mind: these are incidents we know about, not including incidents that went undetected. https://blog.citp.princeton.edu/2022/03/09/attackers-exploit-fundament… Noteworthy: "Additionally, some BGP attacks can still fool all of a CA’s vantage points. To reduce the impact of BGP attacks, we need security improvements in the routing infrastructure as well. In the short term, deployed routing technologies like the Resource Public Key Infrastructure (RPKI) could significantly limit the spread of BGP attacks and make them much less likely to be successful. ... In the long run, we need a much more secure underlying routing layer for the Internet."

Here's details of this attack for people who want more details https://citp.princeton.edu/our-work/memory/ If memory serves correctly they achieved the best results by using a can of compressed air to freeze the ram in place before removal. //Small edit to wording

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The Princeton bitcoin textbook is also excellent (see https://citp.princeton.edu/the-princeton-bitcoin-textbook-is-now-freel… - it is easy to find PDFs online)

Even without refreshing the cells they actually last quite a lot longer than you would expect. This is an old research paper on the topic but unfortunately, it looks like all of the images and videos are broken which is a shame because it gave you a great mental picture of the "half-life" so to speak of RAM. https://citp.princeton.edu/research/memory/ The bottom line is that you would need to stop refreshing it for minutes if not longer to be sure that there wasn't an information leak and if the memory is cooled down it'll last a great deal longer without being refreshed and even still keep the majority of the contents after hours of being removed from a running system if they are cooled using liquid nitrogen. Either way one or two cycles isn't going to really matter at all.

This is very similar to work done by J. Alex Halderman et al. in 2008 [1]. If you find this interesting, check out their paper. They give an example of a bitmap image in memory and its degradation over a number of seconds without power. It's a fantastic visual aid and you might be surprised by how well the data survives; if you're fast (5 seconds) it's nearly lossless. [1] https://citp.princeton.edu/research/memory/

This is super badass! I guess a lot of Proper Security People might say "whatever.. this requires physical access and once you have physical access you can compromise anything", but to truly say you can compromise any physically accessible system I'm sure you need large amounts of skill and resource. Beating FDE without doing something like [1] is really impressive to me. This is also a really interesting viewpoint on machine/protocol design. [1] https://citp.princeton.edu/research/memory/media/ Edit: Also I wonder if there would be much worth in adding kernel interfaces to say "a new DMA-capable device was hotplugged - userspace should ask the user whether we should give them DMA access"? That would allow you to protect against these attacks without having to disable all your biz.

The raw memory itself isn't safe either. Ed Felton did some great work (2008) where he physically removed the sticks of DRAM from one computer, stuck them in another, and read their contents. But doesn't DRAM lose it's content without continuous power? Not if you turn a can of compressed air upside down and spray the chips first, cooling them to -50C! He used this to recover encryption keys and defeat whole disk encryption. Pretty crazy stuff: https://citp.princeton.edu/research/memory/ update: link to images/videos: https://citp.princeton.edu/research/memory/media/

> GPUs become obsolete in 5 years. Not only that, but they're typically amortized over 5 years, where the actual lifespan usually falls far shorter (1-3 years), adding to the artificial subsidy conditions we see today. So they're gaming the lenders into deferring interest payments as much as possible today so that new competitors don't have the same cheap financing advantage.[0] 0: https://blog.citp.princeton.edu/2025/10/15/lifespan-of-ai-chips-the-30…

Nice write-up. Thanks for sharing. Some may not remember BitKeeper being used to maintain the Linux kernel source code and how a discrepancy was found (22 years ago) between that repo and the CVS repo. This kind of led to git and signed commits that we have today, etc. Here's a short write up: https://blog.citp.princeton.edu/2013/10/09/the-linux-backdoor-attempt-…

I'm guessing that this is originally inspired by Nadia Heninger and Ariel Feldman's aeskeyfind, which was part of our cold boot paper from 2008 https://citp.princeton.edu/our-work/memory/code

Actually, RAM can keep its contents for up to a few minutes after shutdown. See here: https://citp.princeton.edu/research/memory/

When for instance an AES-key is being used by OpenSSL, it is put into a 'struct aes_key_st' which is not random at all but quite easily recognizable when scanning memory. The Cold Boot attack paper by Halderman, Schoen et al. here https://citp.princeton.edu/research/memory/ ...discusses this in detail in chapter 6, Identifying Keys in Memory. EDIT: fixed the reference

https://citp.princeton.edu/research/memory/ A few years ago, I tried this on my own laptop. I didn't have any sort of full disk encryption to test against, so I simply checked the RAM dump for plaintext looking things. Without having cooled the RAM (or opened the computer at all), there was a significant amount of meaningful plain-text. If you are interested in actual data about how effective this is, you should probably ignore my antecedent and look at the research paper in the above link. Given how easy this attack is for its effectiveness, I would be suprised if it is not used.

As pfortuny and ygra say, freezing the RAM makes the memory readable for longer. (https://citp.princeton.edu/research/memory/)

This same method can be used to extract encryption keys from RAM on a desktop computer. https://citp.princeton.edu/research/memory/

This is interesting, but is certainly not novel. I did a talk (in one of my grad school courses) in 2008 summarizing the Princeton research regarding attacks on encryption keys stored in memory (https://citp.princeton.edu/research/memory/). DMA and Firewire were both attack vectors mentioned in that paper. Physical Access == Game Over

Adding to your point that this is old news: https://citp.princeton.edu/research/memory/ [LEST WE REMEMBER: COLD BOOT ATTACKS ON ENCRYPTION KEYS]. I think this was on HN awhile ago... The real news is the commercial tool that implements the memory dumping and key extraction.

So it relies on taking a memory dump, this doesn't sound like anything new, for example you can do similar things with https://citp.princeton.edu/research/memory/code/ which is open source. And you can perform the firewire attack using http://www.breaknenter.org/projects/inception/ Additionally memory can also be dumped via PCI e.g. http://www.grandideastudio.com/portfolio/tribble/ If you're concerned about such attacks you could use an external device which lets you enter a password using its own keyboard, meaning the key is stored in volatile memory on the external device - not accessible via a memory dumping tool. And then don't leave the device plugged into the computer when you're not around. And bruteforce attacks have been around for a while using GPUs for instance Passware's forensic program.

Even if you keep things exclusively in memory, the information is still vulnerable via cold boot attacks: https://citp.princeton.edu/research/memory/

It should be mentioned that in the past the University of Princeton had successfully extracted encryption keys from a cold booted computer after the PC has been completely turned off. They even demonstrate what they had recovered and how many bits has been lost. Check this page and videos: https://citp.princeton.edu/research/memory/ https://citp.princeton.edu/research/memory/media/

2. "with the cryogenic RAM freezing technique, presumably" - errr, no. With the "sit down at the computer and turn off the encryption/copy the data to an external drive technique", I think you'll find. Obvious bullsh*t to anyone technical but sounds 'cool' to your average 14yr old who reads these sort of sites. Errr, actually yes. You may be interested in [1] and [2]. [1] http://citp.princeton.edu/pub/coldboot.pdf [2] http://www.youtube.com/watch?v=JDaicPIgn9U

I feel kind of obligated to mention that you can also solve the same problem if the machine is sitting around fully unlocked (not idle and thus cluing the disk encryption in) with a cold-boot attack -- http://citp.princeton.edu/memory/ . The short version: the contents of RAM are preserved pretty well during power loss if you cool the RAM chips, e.g. by dunking in liquid nitrogen or even just spraying with an inverted air duster, and the encryption key is stored in RAM so that the intended user can access the disk, so you can later recover the key from the frozen RAM.

and yet, http://citp.princeton.edu/memory/ , there's much work to be done on it. According to their findings, FileVault on OS X turned out to be the easiest to break.

Briar is a peer-to-peer encrypted messaging app that has received funding from multiple organizations, including the Open Technology Fund (OTF), which is financed by the U.S. government through the Agency for Global Media [1][2][3]. The OTF was established in 2012 as a program of Radio Free Asia, a U.S. government-funded nonprofit, and became independent in 2019 while continuing to receive congressional appropriations [3]. ## Government Funding and Transparency Briar openly discloses its funding sources on its website, listing support from the Open Technology Fund alongside other organizations like NLnet Foundation, the European Commission's Next Generation Internet programme, Access Now, Internews, and others [1][4]. This transparency is notable—the project does not hide its connection to U.S. government-funded initiatives. The OTF itself supports numerous widely-used internet freedom tools, with over two billion people worldwide reportedly using OTF-supported technologies daily [5]. ## The Security Trade-off Question Your skepticism about government-funded privacy tools reflects a legitimate concern that civil liberties advocates have raised [6]. However, Briar's open-source nature allows independent security audits—it was examined by Cure53 in 2017 and received positive assessments [2]. The project was developed by researchers and activists including Michael Rogers and Eleanor Saitta starting in 2011, with stated motivations around supporting freedom of expression and…

since it seems it has been forgotten, remember the reason Git was created is that Larry McVoy, who ran BitMover, which had been donating proprietary software licenses for BitKeeper to core kernel devs, got increasingly shirty at people working on tools to make BK interoperate with Free tools, culminating in Tridge showing in an LCA talk that you could telnet to the BK server and it would just spew out the whole history as SCCS files. Larry shortly told everyone he wasn't going to keep giving BK away for free, so Linus went off for a weekend and wrote a crappy "content manager" called git, on top of which perhaps he thought someone might write a proper VC system. and here we are. a side note was someone hacking the BitKeeper-CVS "mirror" (linear-ish approximation of the BK DAG) with probably the cleverest backdoor I'll ever see: https://blog.citp.princeton.edu/2013/10/09/the-linux-backdoor-attempt-… see if you can spot the small edit that made this a backdoor: if ((options == (__WCLONE|__WALL)) && (current->uid = 0)) retval = -EINVAL;

I think you get to a point, where you can't trust electronics at all. (Active network or no.) Van Eck phreaking. Optical Time-Domain Eavesdropping [1]. Zero-Day exploits on operating systems, browsers, etc. Built-in vulnerabilities to processors. Backdoors in encryption algorithms. Acoustic Keyboard analysis [2]. Laser Audio detection [3]. Hard drive recovery. DRAM recovery. [4] [1] http://www.rootsecure.net/content/downloads/pdf/optical_tempest_crt.pd… [2] http://www.cs.berkeley.edu/~tygar/papers/Keyboard_Acoustic_Emanations_… [3] http://spie.org/x40847.xml [4] https://citp.princeton.edu/research/memory/ If I wanted to send (very) secure email, I think I would want a Kindle-like device, with an ePaper display, no physical keyboard just a touchscreen, no bluetooth or wifi or 3G or microphone - just a single USB port. I'd install the software I want on it, and then I'd physically destroy the USB port. I'd want 4 AA batteries, no recharge port. I guess it would need a camera, as well. And it would have its own Faraday cage. And a built-in, non-electronic method that slags the RAM and storage with acid; possibly by pulling a pin out. I'd wipe the screen clean, every time I used it. How do I get data out of it? I drop data into a QR code sending system. It would generate one full-screen QR-code like image every second or so. On another computer, I'd have a camera that I'd show the device to, and it would read the QR codes, and…

Before you dive too far into full-disk encryption, you might want to contemplate the consequences of this research: http://news.cnet.com/8301-13578_3-9876060-38.html The paper referenced is available at: http://citp.princeton.edu/pub/coldboot.pdf From that paper, the most salient sentence for this discussion is: "On all of our sample DRAMs, the decay rates were low enough that an attacker who cut power for 60 seconds would recover 99.9% of bits correctly." The long and short is that your password has to be in RAM at some point in order to be matched against what is typed in. RAM decays slowly after a machine has been switched off. As the research shows, one can use a widely-available can of air to make that decay happen even slower. In the process, one can pull the value out of RAM. Note that this is a hardware problem that no software on the market has been able to address. To do so, you would have to be able to validate x against y without having the value of y ever enter RAM. Consequently, a reasonably good tech thief can read the password out of RAM. For the not-so-good tech thief, using passwords and social engineering tricks like being nice to someone and then asking them to watch your stuff for a moment will probably do the trick. I tend to see the various implementations of full-disk encryption as more for peace of mind and mitigation of liability than real security.