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Dreamcatcher-tech

Threat modelling for hunted coders

capital-inversion
Originally published at github.com ・13 min read

“It’s only funny until someone loses an identity”

Contents

  1. Coding Under Threat
  2. Value of anonymous code production
  3. Goals of an Operating Model
  4. Actors in the model
  5. Threat Types
  6. Required Items and Tooling
  7. Architecture
  8. Getting a burner number
  9. Importing existing code
  10. Workstation Procedure
  11. AWS Procedure
  12. Pitfalls
  13. Accessing the Aragon DAO
  14. Deniability
  15. Bastions
  16. Cashing out to fiat
  17. Shutting Down
  18. Contributing to this Article

Coding Under Threat

Deployed software must endure various threats during its operating life, but seldom is the threat to the coding operation itself considered. We think often about the security of our applications, but not so often about the security of ourselves. The ability to keep coding is foundational to every project. Project endurance can be damaged by many things, and maintaining a basic level of anonymity provides a very low cost way to handle many common endurance attacks.

For reference, the four freedoms of open source software are:

  1. The freedom to run the program as you wish, for any purpose.
  2. The freedom to study how the program works, and change it so it does your computing as you wish.
  3. The freedom to redistribute copies so you can help your neighbor.
  4. The freedom to distribute copies of your modified versions to others.

Adhering to these freedoms, one can rapidly come under code production threat if established closed source corporations need to defend themselves in some way. This post deals with the specific case of making open source software, with transparent operations, detached from any identifying information about the contributors.

Value of anonymous code production

  1. For Growth: Anonymous contribution makes it hard to intermingle opinions about the authors from a particular idea or embodiment, allowing a purer form of discourse and evaluation to take place. There can be no discrimination of contributions if the people making them do not know who each other are.

  2. For Safety: Getting sued is time wasting and also costly. Worse, any unresolved court cases will stunt growth as people await the outcome, or are scared off by bullying tactics of attackers. As global activity spreads, the chances of falling afoul of some regulation somewhere approaches certainty, with the only true protection being anonymity.

  3. For maximizing investment: No lawyers fees, no company filings, no administrative costs whatsoever

  4. For Resilience: After being completely burned, one person should be able to reboot the project in a matter of days with only the core keys. This should be possible in the face of censorship, intrusion, or even benign hardware faults

Goals of an Operating Model

Our model is based on a theoretical project operator, called Command, that represents the virtualized interests of the driving group behind the project. In this model Command is the identity to be protected above all else - like the king in a chess game. Command is a stable identity, as opposed to transient, and relies on the accumulation of reputation to enhance promotion and recruitment to the project. The goals of this model are:

  1. To be able to recreate any identity, and prove previous contribution, with just the key material
  2. Cannot be possible to accidentally attempt to push to cloud with the wrong identities or credentials
  3. Tor gateway shutdown results in no possible pushes to github
  4. Be more resistant to human error than a vpn
  5. Friendly developer experience
  6. Rapidly reprovisionable development environment

Actors in the model

  1. Command
  2. Contributors
  3. Operators
  4. Users
  5. Investors
  6. Promoters

Threat Types

Things you might want to be protected from:

  • greed (your own, and others around you)
  • costly fights
  • reputational harm
  • project reputational harm
  • government
  • piracy
  • unpopularity
  • discimination
  • DMCA takedown
  • Patent infringement
  • Tax Collectors
  • Securities commissions across the world
  • Peers
  • Civil lawsuits - those originating from private individuals and companies.
  • Law Enforcement
  • Violence / War
  • Govt raid or wiretap
  • Services subpoena - Github - Aws - Protonmail - Serverless.com
  • Service terms (eg: AWS decides you are unwelcome)
  • Malware compromise
  • Enthusiast investigation
  • Friends and family exposure
  • Employer exposure
  • DDoS

Typically correlation is done using IP addresses, credit cards, and cell phone sim cards. These are crucial pieces of identity to secure anonymously.

Required Items and Tooling

Traceable items needed:

  1. Ether cryptocurrency - about $150USD worth
  2. Bare metal machine with a trusted environment - eg: a fresh install

Cloud services used:

  1. Github private repos
  2. Protonmail
  3. Mega for cloud backup

Key material kept on:

  1. Keepass GPG keys per identity

Architecture

We are using the Whonix workstation in conjunction with VSCode ssh tunneling to have the richness of VSCode development, the speed of a local development environment, as well as obfuscation of IP addresses by tunneling thru TOR. This is how Whonix guarantees nothing can escape the workstation VM:

<img src="./assets/whonix.jpg" width="640"/>

This is how we can use VSCode on our local machine while running the development environment within the Whonix protective ring:

<img src="./assets/vscode.png" width="640"/>

All browsing needs to be done with the TOR browser

Getting a burner number

First you need anonymous money. Send the ETH to the mixer at Tornado.cash. Then use the output funds to purchase a temporary cell phone number from crypton.sh. Use some more of the money to purchase an anonymous credit card from Ezzo - this will be needed to host on AWS.

Importing existing code

If bringing in an existing codebase, make sure it comes in mangled so that the initial commit does not simply map to the last commit of some other repository. To trace attribution, make sure you reference some kind of git tree somewhere, and probably sign something in there. Then you want to get it snapshotted on archive.org and a bunch of other places so it is versioned correctly. Ideally it would automatically peg to the btc blockchain, but we aren’t quite there yet….

Workstation Procedure

  1. Ensure bare metal OS is free from any credentials related to any services or compromise, preferably with reinstall
  2. Install base OS software:

    1. virtualbox, keepass, putty, vscode, torbrowser
  3. Create name for identitiy, and create protonmail and github accounts

    1. Use TOR to access namegen webpages such as https://randomnames.herokuapp.com/# in order to get a completely random name. Or you could just make one up...
    2. Set up a protonmail account, and use the burner number as verification, or pay the $5USD donation fee if you purchased a burner credit card.
    3. Set up a github account using this email account.
    4. Github captcha may require about:config in the Firefox address bar and find security.csp.enable and set it to false, and or use the audio captcha at signin, or else you can't use the tor browser to create the account
  4. Install whonix workstation cli version from https://www.whonix.org/wiki/VirtualBox/CLI

  5. Add a second host only adapter to the workstation vm

  6. Install software on whonix workstation: sudo apt install git openssh-server unzip oathtool

  7. Edit file: /etc/whonix_firewall.d/50_user.conf by adding the line: EXTERNAL_OPEN_PORTS+=" 22 "

  8. Change the base user password

  9. Add following lines to /etc/network/interfaces.d/30_non-qubes-whonix

   auto eth1
   iface eth1 inet static
       address 192.168.56.101
       netmask 255.255.255.0
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  1. Create user account with same name as the fake identity
  2. Follow instructions to set up ssh based editing in vscode: https://code.visualstudio.com/docs/remote/ssh-tutorial
  3. Set up node with this command:
   export SHELL=bash
   curl -fsSL https://github.com/Schniz/fnm/raw/master/.ci/install.sh | bash
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  1. Create ssh key and add to github
  2. Create gpg key for signing commits, and add to github
    1. gpg --full-generate-key --expert (then choose ECC and ECC, then curve 25519, as this makes shorter signatures)
    2. Config git using https://docs.github.com/en/github/authenticating-to-github/managing-commit-signature-verification
    3. git config --global commit.gpgsign true
  3. Save the gpg private key and ssh private key in string fields in keepass
    1. gpg --export-secret-key --armor
    2. cat ~/.ssh/id_rsa
  4. Set up 2FA on github and install oathtool:
   sudo apt install oathtool
   oathtool -b --totp (code from github)
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  1. use visudo to add give all dev group members ability to run whonixcheck:
    1. sudo visudo
    2. %dev ALL=NOPASSWD:/usr/bin/whonixcheck
  2. To access https://client.aragon.org in the TOR browser, open about:config and turn off "privacy.resistFingerprinting" - be sure to turn it back on again when not using aragon. An issue has been filed for this problem: https://github.com/aragon/client/issues/1529
  3. Set an offensive color theme on torbrowser, so it is immediately clear when it is in use. Try not to use regular browser as this can lead to correlation with you IP and identity

AWS Procedure

TODO

Pitfalls

  1. Urls in keepass accounts that when double clicked open protected urls in browser
  2. Linked cloud accounts, that if one cloud service is accessed on clearnet, other might be able to trace back
  3. Dev projects might try to make data requests out to other sites - none of our sites should ever request anything from outside the current realm
  4. Vscode might follow links in code base - turn this off by disabling any kind of vscode link detection in user wide settings
  5. opening one of the anonymous account url's in clearnet by clicking on url in keepass and having it open automatically in default browser, which is not behind tor
  6. Generating information inside the project that can be correlated somehow.
  7. Credit card acquisition
    1. Paying with electronic means
    2. Paying with unwashed crypto
    3. Paying with cash from a bank or foreign exchange branch
    4. Cameras on the purchase spot
    5. Number plate from cameras on purchase spot
    6. Google location tracking on phone during purchase
    7. Recognized by shop merchant
    8. Using card too soon after acquisition
    9. Recommended best practice:
      1. Purchase something from a bakery to break the cash
      2. Use small shops away from city centres
      3. Wear sunglasses, a hood, a mask
      4. Turn off phone before entering
      5. Buy local, but not somewhere frequent, so being in the area isn’t correlated
  8. Identity correlation
    1. Entering password for another account in relation to another account
    2. Accessing a rare page on clearnet, then same page shortly after on tor
    3. Accessing a rare page signed in as a github user, then visiting same page signed in as protected identity over tor
    4. Generating info, like pictures, or names, then using that info in projects
  9. Plugins for tooling - anything that sends telemetry back to some owner
    1. License key information for tooling can be identifying Leaks from handwriting - use a diagramming tool like mermaid

Accessing the Aragon DAO

The DAO is available at https://client.aragon.org/#/dreamcatchertech/

Using TOR browser with metamask extension installed. Cleanest way since wallet is entirely self sovereign, however the extension does introduce some risk to anonymity. The extension should be disabled when not in use on Aragon, and a new Tor identity used whenever it is enabled or disabled. From checking the network activity in the developer tools for the extension, its normal operations all go thru TOR.

For those mostconcerned, we recommend running the browser inside a whonixWorkstation, or compiling the extension from source on github. Worst case a leak will be made to metamask or their services such as infura that maps your eth address to your ip address. This does not compromise anonymity as a producer, but might be undesirable as a funder. Activity in the extension can be traced using about:devtools-toolbox?type=extension&id=webextension%40metamask.io in the url box.

This extension can read every webpage you go to, so only go to the aragon client when it is activated. If the tor process is terminated, the metamask extension cannot access infura, showing that it was fetching over tor. Opt out of any telemetry requests.

Money routing cost comparison:

  • binance > ETH > tornado > metamask swap > DAI Cost of transfer: $50USD tornado contract gas, but could probably get it for 10USD withdrawl from tornado 60USD, cheapest is 24USD
  • binance > DAI > tornado > DAI Cost of transfer: 50USD tornado contract gas withdraw gas fee $3.77

Sending in ETH is better since lets amounts up to 50kUSD go thru, and has more traffic in the anonymity set. Downside is the price of ETH changing while the funds are waiting

Deniability

Always have layered reasons for how you came across any data you might get questioned over. The best way is publishing blogs and projects as soon as possible, spreading these ideas as far as possible.

Make info as public as possible with as much traffic on it as possible. Follow a standard with other people following similar goals. The only secrets should be key material.

It is never about being completely anonymous - its just about not being the biggest fish in the anonymity pond so to speak. For example if the cash mixer service you use is compromised by some state level actor, they won't really want it known that they can compromise it, since they're looking for something serious like a terrorist or war criminal. If all you're trying to do is write software without getting judged for who you are as a human, they are very unlikely to share the information about you with anyone.

Bastions

Techniques The key to anonymity is looking the same as a whole lot of other people. To that end, broadcasting as much information as you can, and following a rigorous set of protocols makes you look the same as anyone else following the plan. We begin by broadcasting our methods to a public blog platform dev.to in order to plausibly say where our info came from

This is all part of our drive towards creating zero liability companies, which thru transparency and the higher hosting context of public blockchains, can have higher trust levels, greater thruput, more direct service, at lower costs.

Now ideally all this procedure would be hard baked in to the protocol, but since this does not yet exist, we have to use discipline and technique to achieve similar end goals.

https://github.blog/2020-02-20-2019-transparency-report/

Github allows pulling code anonymously, so rely on publication of your repo url, the clone with collaborators thru tor

Bastions are isolated networks of operation. There is no cross over between these networks, and no knowledge inside each one of any others. Any bastion breach should not affect any other in any way. They all draw on a common codebase, from the Core. This allows running each corporate venture on an entirely isolated set of infrastructure.

Bastions allow projects to be built atop a potentially swappable blockchain core. The swappability is important should legality force cessation of any particular blockchain, and also to allow migration to the most suitable blockchain, as they become available

Bastion 0: Core Bastion 1: CRM Allowed to use for commercial demonstrations locally Bastion 2: Commercial demos Bastion N: any endeavours that need isolation

Each bastion must have completely separate identity and infrastructure to the others, and have no contact. Code sharing must be done offline. Only danger is going to anon github urls while logged in to github, which only matters if github gets breached, and should be covered by publicizing the urls.

https://ssd.eff.org/en/module/your-security-plan

Keep the infrastructure hidden - the worst thing that could happen is your site is offline - this is a loss of a potential user, supporter, contributor, or investor. Uptime under duress is hard

No bastion identities can come in contact with any others. If they need to share code it needs to be via offline means. Leakage from one browsing anothers github repos while logged in is only damaging if github is breached. Always protect the infrastructure.

Sharing libraries between bastions:

  1. nominate one user as the library owner
  2. in each repo, stored in their home dir, chmod .git 700 so that no accidental commits can be made by any other user, leaking the relationship between users
  3. make a group shared between the dev accounts called 'dev'

Cashing out to fiat

For the best price and trust, use an exchange like binance.com but be aware you will need to pass KYC verification. If you need to cash out anonymously, then the best way to do that is using local based exchanges. These exchanges help you conduct trades with people individually. For example, selling BTC, DAI, or ETH to a local user results in about 1% below market loss, but will take about 15 minutes for the funds to arrive, and most importantly will result in a direct person to person transfer into your bank account.

Alternatively you might choose to get a crypto based visa card to let you spend directly. Local exchanges of note are:

  • localbitcoins.com - the original, very reliable, requires KYC
  • localcryptos.com - good volume, no KYC

Depending on your jurisdiction, you may owe taxes and levies to your local government. These fees usually become due at time of withdrawl, so be sure you know your responsibilities here. Remember the fiat money system was built by your government, and so they have the right to do whatever they wish with it, including levying taxes.

DAI is a good base to run your venture on because:

  • DAI being pegged to USD is stable relative to Bitcoin or any other crypto asset which has a thinly traded marketplace relative to USD
  • DAI can be run thru a mixer such as Tornado.cash which makes it difficult to trace the origin of the funds whilst still giving investors the option to prove it was them in the future.
  • DAI is not subject to the US Federal reserve, which owns all USD, and can seize USD backed coins such as Tether and others based on their operational policies. DAI is virtual, and not subject to those forces, altho it has a different set of weaknesses

Shutting Down

If things haven't worked out, or you have been compromised, then destroying the key material should be all that is required to separate yourself from the project. You may wish to also reset all your machines to factory default. To help your peers, leaving your repositories open and available would be appreciated, and if you can identify the source of your leak, please let others know and suggest updates to the Operating Model, so that all might benefit.

Contributing to this Article

If you've found an error, a typo, a sentence that could be improved or anything else that should be updated on this blog post, you can access it through its Github repository. Please open a pull request or an issue with the changes you want.

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