Skip to content
  • Home Home Home, current page.
  • Moments Moments Moments, current page.

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
backus's profile
John Backus
John Backus
John Backus
@backus

Tweets

John Backus

@backus

Seeking alternative compression. Hopefully wrong on average. Shameless. Started @getcognito and @bloom

San Francisco, CA
Joined August 2012

Tweets

  • © 2018 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. John Backus‏ @backus Jan 20

      Detecting an unlock from an unfocused tab is especially sketchy in my opinion. This means any app can detect when you are in the middle of *using* your Ethereum wallet.

      2 replies 7 retweets 52 likes
      Show this thread
    2. John Backus‏ @backus Jan 20

      If the user just unlocked their wallet for another tab then they are probably about to send a transaction. The attacker can detect the unlock, wait 30 seconds, then pop up their own transaction. Attached gif is an example attack when the user is in the middle of using an exchangepic.twitter.com/1FljviXydN

      3 replies 30 retweets 99 likes
      Show this thread
    3. John Backus‏ @backus Jan 20

      A lot of other small attack opportunities IMO that exist as long as web3 is injected into every page. You can tell if someone is specifically a Metamask user by checking `web3.currentProvider.isMetamask`. Why not pop up your own Metamask lookalike in the top right?pic.twitter.com/gw8drsiE3k

      1 reply 8 retweets 48 likes
      Show this thread
    4. John Backus‏ @backus Jan 20

      Regardless of whether the wallet is currently locked, you can use the current network id on web3 to see if the user was last using the testnet or mainnet. If they're on anything besides mainnet, they are probably a developer and likely have higher than average crypto holdings.

      1 reply 6 retweets 30 likes
      Show this thread
    5. John Backus‏ @backus Jan 20

      To give Metamask credit, they do have several issues on Github open discussing issues around globally available web3 instance: - https://github.com/MetaMask/metamask-extension/issues/799 … - https://github.com/MetaMask/metamask-extension/issues/12 … - https://github.com/MetaMask/metamask-extension/issues/537 … -https://github.com/MetaMask/metamask-extension/issues/714 …

      1 reply 5 retweets 40 likes
      Show this thread
    6. John Backus‏ @backus Jan 20

      In my opinion, the best immediate stopgap these extensions should add is something similar to other browser permissions like how we grant access to location information. I think the Metamask team is looking into doing this long term: https://github.com/MetaMask/metamask-extension/issues/813 …pic.twitter.com/AM6KUpIIoP

      1 reply 8 retweets 36 likes
      Show this thread
    7. John Backus‏ @backus Jan 20

      Potential short term solution: 1. Hardcode that only http://metamask.io/whitelist  can call invoke some whitelist functionality in extension 2. dApps opens popup for http://metamask.io/whitelist?url=example.com … 3. Extension asks if you want to give http://example.com  access to your wallet

      1 reply 7 retweets 42 likes
      Show this thread
    8. John Backus‏ @backus Jan 20

      Restricting this functionality to their domain means that nothing has to be injected into every page. Popup means any page can really easily initiate the whitelist process without having to write browser vendor specific extension interactions.

      1 reply 4 retweets 20 likes
      Show this thread
    9. John Backus‏ @backus Jan 20

      Short term solution would then be to add whitelisting as an opt-in feature (so you don't break existing integrations and make people regret writing their app to depend on Metamask). Security conscious users can opt-in right away and app developers can plan for deprecation.

      1 reply 3 retweets 20 likes
      Show this thread
    10. John Backus‏ @backus Jan 20

      In the meantime, I'd recommend users disable Metamask by default in their browser and then enable it when they want to use it. Unlike unlocking a wallet, I wasn't able to detect (from an already open and unfocused tab) when a disabled extension was enabled.pic.twitter.com/Tn3GCVeMuH

      4 replies 12 retweets 44 likes
      Show this thread
      John Backus‏ @backus Jan 20

      Some UI improvements would also help the transaction spoofing example I gave. The browser should switch to the tab that created the transaction. The confirmation window should probably have a brightly colored banner that says "http://example.com  created this transaction."pic.twitter.com/eYJ60CpZVN

      8:21 PM - 20 Jan 2018
      • 3 Retweets
      • 31 Likes
      • James Jayi Wang Pat Fives Bharath Ramsundar Le Quoc Viet Jordan Arseno Cryptoks Stefan Jake Rockland VivekOMON
      2 replies 3 retweets 31 likes
        1. New conversation
        2. John Backus‏ @backus Jan 20

          Metamask and other browser wallets are in a tough position though with these transaction popups. If a legitimate dApp could put a custom message in the confirmation window then an attacker could mimic it.

          1 reply 1 retweet 18 likes
          Show this thread
        3. John Backus‏ @backus Jan 20

          I'd love to see is the ability to use an ENS address as the recipient field in a transaction. For @BloomToken, users are currently interacting with one of two contracts. If our end users saw our ENS address for every transaction then they'd be less likely to fall for a spoof.

          2 replies 3 retweets 22 likes
          Show this thread
        4. John Backus‏ @backus Jan 20

          I also want to clarify that I'm not saying that people should never use these in-browser wallets. Security is especially tough and nuanced when you are a platform for handling money and user identity. Even harder when you are on the development side of early adoption.

          1 reply 2 retweets 24 likes
          Show this thread
        5. John Backus‏ @backus Jan 20

          In-browser wallets should be unlocked *per domain*. An advertiser shouldn't be able to log my ETH address in an unfocused tab just because I want to check on my crypto kitties.

          2 replies 4 retweets 33 likes
          Show this thread
        6. John Backus‏ @backus Jan 20

          I'd also love to see at least an opt-in setting that locks my wallet again after sending a transaction. If a dApp wants to send multiple transactions without unlocking between each, they can use `web3.createBatch`. Metamask handles this well already

          1 reply 2 retweets 22 likes
          Show this thread
        7. John Backus‏ @backus Jan 20

          An attack that sent ERC20 tokens would be effective. Unlike moving ETH (where Metamask would say how much ETH you are sending), a token transaction would just display the gas price AFAIK. More likely to trick people if they can't tell what is being sent.

          1 reply 2 retweets 30 likes
          Show this thread
        8. John Backus‏ @backus Jan 21

          John Backus Retweeted John Backus

          If you enjoyed this thread on in-browser wallet security, I started a separate thread about community security when running a token sale:https://twitter.com/backus/status/955241954320662528 …

          John Backus added,

          John Backus @backus
          The Ethereum Scam Database (http://etherscamdb.info ) is a great resource. Maintained by @myetherwallet and enforced by @metamask_io. We've had hundreds of scammers trying to impersonate @BloomToken and I always report addresses and phishing URLs. pic.twitter.com/9fSSJvz84i
          Show this thread
          2 replies 6 retweets 13 likes
          Show this thread
        9. John Backus‏ @backus Jan 22

          I turned this thread into a full blog post and also included a few updates! Checkouthttps://blog.hellobloom.io/using-an-in-browser-ethereum-wallet-heres-some-things-you-should-know-e01304b977e3 …

          3 replies 5 retweets 14 likes
          Show this thread
        10. End of conversation
        1. Dan Finlay‏ @danfinlay Jan 20
          Replying to @backus

          Surprised to realize we don’t! That was in out first UI, I guess we didn’t add it back yet… (adding ticket)

          0 replies 0 retweets 1 like
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2018 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Cookies
        • Ads info