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
tehjh's profile
Jann Horn
Jann Horn
Jann Horn
@tehjh

Tweets

Jann Horn

@tehjh

works at Google Project Zero. personal account.

Joined August 2011

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. Micah Lee‏Verified account @micahflee Feb 24
      • Report Tweet
      • Report NetzDG Violation

      For the last few months I've been working on an exciting new tool called DANGERZONE. It lets you convert potentially malicious PDFs or office documents into PDFs that you know are safe. I'll be releasing it at @nullcon in Goa, India!pic.twitter.com/18RlIkJknR

      46 replies 359 retweets 1,442 likes
    2. Andreas Rasmussen‏ @flinkeandreas Feb 24
      • Report Tweet
      • Report NetzDG Violation
      Replying to @micahflee @nullcon

      Awesome! Qubes' tool to create trusted pdf's is really nice as well.

      1 reply 0 retweets 9 likes
    3. Micah Lee‏Verified account @micahflee Feb 24
      • Report Tweet
      • Report NetzDG Violation
      Replying to @flinkeandreas @nullcon

      The @QubesOS TrustedPDF was my inspiration for this project, actually. It basically does the exact same thing (with some extra stuff, like OCR and compression), but using containers instead of VMs

      1 reply 6 retweets 51 likes
    4. Jann Horn‏ @tehjh Feb 24
      • Report Tweet
      • Report NetzDG Violation
      Replying to @micahflee @flinkeandreas and

      why containers? wouldn't it be more efficient, and safer, to first load the pdf->image conversion code into memory, then open a file descriptor to the PDF without looking at it yet, then install a highly restrictive seccomp filter, and then do the parsing?

      1 reply 2 retweets 9 likes
      Jann Horn‏ @tehjh Feb 24
      • Report Tweet
      • Report NetzDG Violation
      Replying to @tehjh @micahflee and

      with a bit of work, you can probably limit yourself to exit_group(), read(), write() and mmap() with extremely restricted flags for allocating memory

      1:57 PM - 24 Feb 2020
      • 6 Likes
      • sudo apt purge testosterone ⬡ Jens Wiechers Jens Kubieziel Jesse Michael Aaron Grattafiori Leonardo Porpora
      2 replies 0 retweets 6 likes
        1. New conversation
        2. Devdatta Akhawe‏ @frgx Feb 24
          • Report Tweet
          • Report NetzDG Violation
          Replying to @tehjh @micahflee and

          I would love to see this if it happened. All the PDF processors we tried need a lot of other syscalls for some reason or the other. I am thinking of trying the Adobe WASM based SDK for PDF previews next -- that should be solid and easy to sandbox.https://medium.com/adobetech/acrobat-on-the-web-powered-by-webassembly-782385e4947e …

          1 reply 1 retweet 2 likes
        3. Jann Horn‏ @tehjh Feb 24
          • Report Tweet
          • Report NetzDG Violation
          Replying to @frgx @micahflee and

          [1/3] really? I ran poppler's "pdftoppm" on some random pdf, and its syscalls after opening the PDF look like this: https://gist.github.com/thejh/38cbe890f83975640a823b3278ade2f6 … - grouped by category:

          1 reply 0 retweets 1 like
        4. 4 more replies
        1. New conversation
        2. Micah Lee‏Verified account @micahflee Feb 24
          • Report Tweet
          • Report NetzDG Violation
          Replying to @tehjh @flinkeandreas and

          I specifically wanted it to be cross-platform and simple to run in macOS and Windows as well. And using containers also makes the work much simpler -- the conversion is done by tools like headless libreoffice, poppler, imagemagick. I didn't want to have to re-invent all that

          1 reply 0 retweets 10 likes
        3. Jann Horn‏ @tehjh Feb 24
          • Report Tweet
          • Report NetzDG Violation
          Replying to @micahflee @flinkeandreas and

          so actually on macOS and Windows you are using VMs?

          1 reply 0 retweets 3 likes
        4. 8 more replies

      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