Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

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
colmmacc's profile
Colm MacCárthaigh
Colm MacCárthaigh
Colm MacCárthaigh
@colmmacc

Tweets

Colm MacCárthaigh

@colmmacc

AWS, Apache, Crypto, Irish Music, Haiku, Photography

Seattle
notesfromthesound.com
Joined April 2008

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • 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. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      Calling SSL_shutdown() twice is normal when there's no problem with a connection, and it should be harmless in the error case, so it's understandable that some applications do it ... but thankfully it's not common.

      1 reply 0 retweets 1 like
      Show this thread
    2. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      The actual leak of info, whether it was a padding or MAC error, would effectively show up as a timing or connection close difference between these calls. Impacted applications would either seem to time out, or close connections, differently, depending on the error. Subtle.

      1 reply 0 retweets 4 likes
      Show this thread
    3. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      O.k. so next question: why don't existing padding oracle tests find this? Well it turns out only to happen to zero byte records. Records that have no data in them. And the scanning tool happens to send zero byte records.

      1 reply 0 retweets 2 likes
      Show this thread
    4. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      Zero-byte records aren't common: browsers don't send them afaict, and packet dumps seem to show that they are exceedingly rare: which makes sense, if you have no data to send, why would bother? So that's very re-assuring.

      1 reply 1 retweet 2 likes
      Show this thread
    5. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      Next weird thing: the problem also happened if OpenSSL wasn't using AES-NI hardware acceleration. In practice this means it impacted 3DES (which people should have turned off for other reasons!) and older hardware.

      1 reply 1 retweet 3 likes
      Show this thread
    6. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      This also explained why FIPS software appeared in the list, because FIPS software generally can't use AES-NI.

      1 reply 0 retweets 2 likes
      Show this thread
    7. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      At this point, a lot of factors have to be combined: TLS sw would have to be coded in an uncommon way, using OpenSSL, negotiating older cipher suites, on older HW, with clients that send 0-byte records, and can be made repeat the same data over and over, with an active MITM.

      2 replies 1 retweet 2 likes
      Show this thread
    8. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      But that makes it more interesting! How do we find and prevent even these kind of rarefied cases? Automation, like the scanning tool, is clearly critical - but can we do more at the point of code?

      1 reply 0 retweets 3 likes
      Show this thread
    9. Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation

      One thing I'm grateful for is that in s2n we kill connections on any error, and we do it in a way where s2n will completely refuse to interact with the connection after the error has happened. Just with a closed flag ... https://github.com/awslabs/s2n/blob/master/tls/s2n_connection.c#L1031 …

      2 replies 1 retweet 1 like
      Show this thread
    10. Brian Smith‏ @BRIAN_____ 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @colmmacc

      Does it send alerts? This was one of the reasons I argued that sending (error) alerts should be optional in TLS 1.3. (Early drafts mandated the sending of alerts.)

      1 reply 0 retweets 0 likes
      Colm MacCárthaigh‏ @colmmacc 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @BRIAN_____

      Nope! s2n never sends alerts in the error cases, it just pulls the rip-cord and closes() the connection after a uniformly randomized delay of between 10 and 30 seconds ... granular to nanoseconds.

      11:44 AM - 26 Feb 2019
      • 2 Likes
      • Alex Weibel Eyal Ronen
      0 replies 0 retweets 2 likes

      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

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info