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.
  • 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
andreasdotorg's profile
andreasdotorg
andreasdotorg
andreasdotorg
@andreasdotorg

Tweets

andreasdotorg

@andreasdotorg

I'm a hacker, pretty much in the old school sense of the word. But I do know IT security too.

Joined April 2008

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. andreasdotorg‏ @andreasdotorg Apr 1

      andreasdotorg Retweeted Michael Burge

      Of course, with a memory-safe language, W^X is not a needed mitigation. With runtime compilation, it is, as illustrated here, even in the way.https://twitter.com/TheMichaelBurge/status/978381073506643968 …

      andreasdotorg added,

      Michael Burge @TheMichaelBurge
      Security people: You shouldn't allocate memory that is both writable and executable. Developers: Okay. But I'll automate switching between them before every write or execute. https://github.com/racket/racket/commit/9d0ab74e9e46cbdb7e95d1398fdbc985a9527b61 …
      3 replies 3 retweets 12 likes
      Show this thread
    2. CopperheadOS‏ @CopperheadOS Apr 1
      Replying to @andreasdotorg

      A memory safe language still has a substantial trusted computing base of potentially memory unsafe code. Those mitigations don't lose their value. Making it trivial to exploit a heap overflow vulnerability like this once it's found isn't a great plan: https://github.com/rust-lang/rust/blob/c661e385fd81afef808f414867cc44a6c897195e/src/liballoc_system/lib.rs#L332-L333 ….

      2 replies 0 retweets 2 likes
    3. andreasdotorg‏ @andreasdotorg Apr 1
      Replying to @CopperheadOS

      Umm, returning to scheme_eval_string makes any control of instruction pointer in a process instant easy code execution, W^X or not.

      1 reply 0 retweets 0 likes
    4. CopperheadOS‏ @CopperheadOS Apr 1
      Replying to @andreasdotorg

      An attacker being able to overwrite a function pointer or return address doesn't mean they can run any code in the process. They need to choose code that the CFI implementation permits calling from there and they need to be able to point it at the dynamic address of that code.

      1 reply 0 retweets 1 like
    5. andreasdotorg‏ @andreasdotorg Apr 1
      Replying to @CopperheadOS

      scheme_eval_string is a legit entry point. Your CFI won't save you.

      1 reply 1 retweet 1 like
    6. CopperheadOS‏ @CopperheadOS Apr 1
      Replying to @andreasdotorg

      Not quite sure what you mean by that. Clang CFI will permit calling it if the type signature matches the calling site, which it might. An attacker will often only have control over function pointers in the heap via use-after-free, etc. and those often have restrictive types.

      2 replies 0 retweets 1 like
      andreasdotorg‏ @andreasdotorg Apr 1
      Replying to @CopperheadOS

      I might be confused about what clang CFI is doing there differently, going to read up on it. The CFI implementations I'm familiar with are mainly concerned about jumping into the middle of a function body for ROP primitive building.

      6:37 AM - 1 Apr 2018
      1 reply 0 retweets 0 likes
        1. New conversation
        2. CopperheadOS‏ @CopperheadOS Apr 1
          Replying to @andreasdotorg

          That's Microsoft CFG and what Intel CET do for function pointers (along with not allowing function pointers to call functions that are identified as not indirectly callable) but Clang CFI is type-based.

          2 replies 0 retweets 1 like
        3. andreasdotorg‏ @andreasdotorg Apr 1
          Replying to @CopperheadOS

          Just noticing: if any of these control flow mechanisms stop an exploit, they do so regardless of whether W^X is active.

          1 reply 0 retweets 0 likes
        4. CopperheadOS‏ @CopperheadOS Apr 1
          Replying to @andreasdotorg

          In the more narrow cases where they actually stop a vulnerability from being exploited, they don't really need that, but for powerful primitives like arbitrary write they aren't much good at making it harder to exploit if the attacker can just overwrite executable code.

          2 replies 0 retweets 0 likes
        5. andreasdotorg‏ @andreasdotorg Apr 1
          Replying to @CopperheadOS

          We're talking about a very specific case here: having Racket in memory. Now w.r.t. CFI, there are two subcases: 1. CFI stops the attack. W^X is not needed. 2. CFI doesn't stop the attack. Attacker calls scheme_eval_string(). W^X doesn't stop the attack.

          1 reply 0 retweets 0 likes
        6. andreasdotorg‏ @andreasdotorg Apr 1
          Replying to @andreasdotorg @CopperheadOS

          Or as a corrolary: if you can call eval(), W^X is security theater.

          1 reply 0 retweets 0 likes
        7. CopperheadOS‏ @CopperheadOS Apr 1
          Replying to @andreasdotorg

          It can essentially always be bypassed even without eval(...) or an interpreter though. It only puts up a small barrier to exploitation, but that can be very valuable when considering how difficult it can be to make reliable memory corruption exploits.

          2 replies 0 retweets 0 likes
        8. andreasdotorg‏ @andreasdotorg Apr 1
          Replying to @CopperheadOS

          If eval() isn't there, it increases effort for the attacker, yes. With eval(), it doesn't make any difference at all.

          1 reply 0 retweets 0 likes
        9. CopperheadOS‏ @CopperheadOS Apr 1
          Replying to @andreasdotorg

          An attacker needs to find the address of eval and a function pointer / return address to overwrite with it along with setting it up to properly pass a pointer to their code. It's not that much different from them being able to call system(...) in libc to run /bin/sh code.

          1 reply 0 retweets 0 likes
        10. 2 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

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