BitCluster Brings a New Way to Snoop Through BitCoin Transactions

Mining the wealth of information in the BitCoin blockchain is nothing new, but BitCluster goes a long way to make sense of the information you’ll find there. The tool was released by Mathieu Lavoie and David Decary-Hetu, PH.D. on Friday following their talk at HOPE XI.

I greatly enjoyed sitting in on the talk which began with some BitCoin basics. The cryptocurrency uses user generated “wallets” which are essentially addresses that identify transactions. Each is established using key pairs and there are roughly 146 million of these wallets in existence now

If you’re a thrifty person you might think you can get one wallet and use it for years. That might be true of the sweaty alligator-skin nightmare you’ve had in your back pocket for a decade now. It’s not true when it comes to digital bits —  they’re cheap (some would say free). People who don’t generate a new wallet for every transaction weaken their BitCoin anonymity and this weakness is the core of BitCluster’s approach.

Every time you transfer BitCoin (BTC) you send the network the address of the transaction when you acquired the BTCs and sign it with your key to validate the data. If you reuse the same wallet address on subsequent transactions — maybe because you didn’t spend all of the wallet’s coins in one transaction or you overpaid and have the change routed back to your wallet. The uniqueness of that signed address can be tracked across those multiple transactions. This alone won’t dox you, but does allow a clever piece of software to build a database of nodes by associating transactions together.

Mathieu’s description of first attempts at mapping the blockchain were amusing. The demonstration showed a Python script called from the command line which started off analyzing a little more than a block a second but by the fourth or fifth blocks hit the process had slowed to a standstill that would never progress. This reminds me of some of the puzzles from Project Euler.

bitcluster-how-it-worksAfter a rabbit hole of optimizations the problem has been solved. All you need to recreate the work is a pair of machines (one for Python one for mondoDB) with the fastest processors you can afford, a 500 GB SSD, 32 GB of RAM (but would be 64 better), Python 64-bit, and at least a week of time. The good news is that you don’t have to recreate this. The 200GB database is available for download through a torrent and the code to navigate it is up on GitHub. Like I said, this type of blockchain sleuthing isn’t new but a powerful open source tool like this is.

Both Ransomware and illicit markets can be observed using this technique. Successful, yet not-so-cautious ransomers sometimes use the same BitCoin address for all payments. For example, research into a 2014 data sample turned up a ransomware instance that pulled in $611k (averaging $10k per day but actually pulling in most of the money during one three-week period). If you’re paying attention you know using the same wallet address is a bad move and this ransomware was eventually shut down.

Illicit markets like Silk Road are another application for BitCluster. Prior research methods relied on mining comments left by customers to estimate revenue. Imagine if you had to guess at how well Amazon was doing reading customer reviews and hoping they mentioned the price? The ability to observe BTC payment nodes is a much more powerful method.

A good illicit market won’t use just one wallet address. But to protect customers they use escrow address and these do get reused making cluster analysis possible. Silk Road was doing about $800k per month in revenue at its height. The bulk of purchases were for less than $500 with only a tiny percentage above $1000. But those large purchases were likely to be drug purchases of a kilo or more. That small sliver of total transactions actually added up to about a third of the total revenue.

bitcluster-logoIt’s fascinating to peer into transactions in this manner. And the good news is that there’s plenty of interesting stuff just waiting to be discovered. After all, the blockchain is a historical record so the data isn’t going anywhere. BitCluster is intriguing and worth playing with. Currently you can search for a BTC address and see total BTC in and out, then sift through income and expense sorted by date, amount, etc. But the tool can be truly great with more development. On the top of the wishlist are automated database updates, labeling of nodes (so you can search “Silk Road” instead of a numerical address), visual graphs of flows, and a hosted version of the query tool (but computing power becomes prohibitive.)

Bunnie and Snowden Explore iPhone’s Hackability

[Bunnie Huang] and [Edward Snowden] have teamed up to publish a paper exploring the possibility of introspection on the iPhone.

A rendering of the proposed introspection device attached to an iPhone6
A rendering of the proposed introspection device attached to an iPhone6

The idea is that phones are increasingly complex and potentially vulnerable to all kinds of digital surveillance. Even airplane mode is insufficient for knowing that your phone isn’t somehow transmitting information. The paper looks at the various radios on the iPhone, going so far as opening up the device and reading signals at each of the chips for cell, WiFi, Bluetooth, GPS, and NFC to determine whether the chip itself is doing anything, regardless of what the screen says. This introspection can then be used to be confident that the phone is not communicating when it shouldn’t be.

The paper goes on to propose a device that they will prototype in the coming year which uses an FPC that goes into the phone through the SIM card port. It would contain a battery, display, buttons, multiple SIM cards, and an FPGA to monitor the various buses and chips and report on activity.

Significant hacking of an iPhone will still be required, but the idea is to increase transparency and be certain that your device is only doing what you want it to.

Bunnie and EFF Sue US Government over DMCA 1201

This morning Bunnie Huang wrote about his reasons for suing the US Government over Section 1201 of the Digital Millennium Copyright Act (DMCA).

The DMCA was enacted in 1996 and put in place far-reaching protections for copyright owners. Many, myself included, think these protections became far-overreaching. The DMCA, specifically section 1201 of the act which is known as the anti-circumvention provision, prohibits any action that goes around mechanisms designed to protect copyrighted material. So much has changed since ’96 — software is now in every device and that means section 1201 extends to almost all electronics sold today.

So protecting copyright is good, right? If that were the only way section 1201 was enforced that might be true. But common sense seems to have gone out the window on this one.

If you legally purchase media which is protected with DRM it is illegal for you to change the format of that media. Ripping your DVD to a digital file to view on your phone while on the plane (something usually seen as fair use) is a violation. Want to build an add-on for you home automation system but need to reverse engineer the communications protocol first? That’s a violation. Perhaps the most alarming violation: if you discover a security vulnerability in an existing system and report it, you can be sued under DMCA 1201 for doing so.

Cory Doctorow gave a great talk at DEF CON last year about the Electronic Frontier Foundation’s renewed push against DMCA 1201. The EFF is backing Bunnie on this lawsuit. Their tack argues both that section 1201 is stiffling innovation and discouraging meaningful security research.

If it’s illegal to write about, talk about, or even privately explore how electronics are built (and the ecosystem that lets them function) it’s hard to really master creating new technology. A successful lawsuit must show harm. Bunnie’s company, Alphamax LLC, is developing hardware that can add an overlay to an HDMI signal (which sounds like the continuation of the hack we saw from him a few years ago). But HDCP would prevent this.

Innovation aside, the security research angle is a huge reason for this law (or the enforcement of it) to change. The other plaintiff named in the suit, Matthew Green, had to seek an exemption from the DMCA in order to conduct his research without fear of prosecution. Currently there is a huge disincentive to report or even look for security vulnerabilities, and that is a disservice to all. Beneficial security research and responsible disclosure need to be the top priority in our society which is now totally dependent on an electronically augmented lifestyle.

MIT Thinks It Can One-Up TOR With New Anonymity Network: Riffle

Tor is the household name in anonymous networks but the system has vulnerabilities, especially when it comes to an attacker finding out who is sending and receiving messages. Researchers at MIT and the École Polytechnique Fédérale de Lausanne think they have found a better way in a system called Riffle. You can dig into the whitepaper but the MIT news article does a great job of providing an overview.

The strength at the core of Tor is the Onion Routing that makes up the last two letters the network’s name. Riffle keeps that aspect, building upon it in a novel way. The onion analogy has to do with layers of skins — a sending computer encrypts the message multiple times and as it passes through each server, one layer of encryption is removed.

Riffle starts by sending the message to every server in the network. It then uses Mix Networking to route the message to its final destination in an unpredictable way. As long as at least one of the servers in the network is uncompromised, tampering will be discovered when verifying that initial message (or through subsequent authenticated encryption checks as the message passes each server).

The combination of Mix Networking with the message verification are what is novel here. The message was already safe because of the encryption used, but Riffle will also protect the anonymity of the sender and receiver.

[via Engadget]

Data Exfiltration With Broadcast Radio And CD-ROM Drives

The first music played on personal computers didn’t come out of fancy audio cards, or even a DAC. the first audio system in a personal computer was simply holding an AM radio up to the case and blinking address pins furiously. This worked wonderfully for homebrew computers where EMC compliance hadn’t even become an afterthought, but the technique still works today. [Chris] is playing music on the radio by sending bits over the system bus without using any wires at all.

[Chris]’ code is based on the earlier work of [fulldecent], and works pretty much the same. To play a sound over the radio, the code simply writes to a location in memory when the waveform should be high, and doesn’t when the waveform is low.

Of course the ability to exfiltrate information over an airgap has a few more nefarious purposes, but [Chris] also has another way of doing just that which is undefeatable by a TEMPEST shielded computer. He can send one bit at a time by opening and closing a CD-ROM drive, capturing these bits with a webcam. Is it useful? It’s hard to imagine how this setup could ever capture any valuable data, but it is a proof of concept.

Removing DRM From Aaron Swartz’s eBook

After his death, Aaron Swartz became one of the Internet’s most famous defenders of the free exchange of information, one of the most polarizing figures on the topic of intellectual property, and the most famous person that still held on to the ideals the Internet was founded on. Aaron was against DRM, fought for the users, and encouraged open access to information.

Early this year, Verso Books published the collected writings of Aaron Swartz. This eBook, according to Verso, contains ‘social DRM’, a watermarking technology that Verso estimates will, “contribute £200,000 to the publisher’s revenue in its first year.” This watermarking technology embeds uniquely identifiable personal information into individual copies of eBooks.

With a heavy sigh, you realize you do not live in the best of all possible worlds.

The Institute for Biblio-Immunology had a similar reaction to Verso Books’ watermarking technology applied to the collected writings of Aaron Swartz. In a communique released late last weekend, they cracked this watermarking scheme and released the code to remove this ‘social DRM’ from ePub files.

The watermarking technology in Aaron Swartz’s eBook comes courtesy of BooXtream, a security solution where every eBook sold is unique using advanced watermarking and personalization features. “A publication that has been BooXtreamed can be traced back to the shop and even the individual customer,” the BooXtream website claims, and stands in complete opposition to all of Aaron Swartz’s beliefs.

After analyzing several digital copies of Aaron Swartz’s eBook, the Institute for Biblio-Immunology is confident they have a tool that removes BooXtrem’s watermarks in EPUB eBooks. Several watermarks were found, including the very visible – Ex Libris images, disclaimer page watermarks, and footer watermarks – and the very hidden, including image metadata, filename watermarks, and timestamp fingerprints.

While the Institute believes this tool can be used to de-BooXtream all currently available ‘social DRM’ed’ eBooks, they do expect the watermarking techniques will be quickly modified. This communique from the Institute of Biblio-Immunology merely provides the background of what BooXtream does, not the prescription for the disease of ‘social DRM’. These techniques can be applied to further social DRM’ed eBooks, which, we think, is what Aaron would have done.

Coolest, but Least Secure, Security Device

[Matikas] apparently forgets to lock the screen on his computer when he gets up to grab a coffee. And he apparently works with a bunch of sharks: “If you don’t [lock it], one of your colleagues will send email to the whole company that you invite them to get some beer (on your bill, of course).” Not saying we haven’t done similar, mind you. Anyway, forgetting to lock your screen in an office environment is serious business.

So [Matikas] built a great system that remotely types the keystrokes to lock his screen, or unlock it with his password. An off-the-shelf 433 MHz keyfob is connected to an Arduino micro that simulates a keyboard attached to his computer. It’s a simple system, but it’s a great effect. (See the video demo, below.)

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