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    Hanno Böck

    blog.hboeck.de · Personal blog · on HN since 2014

    Hanno Böck, a security researcher and journalist, writes about vulnerabilities, cryptography flaws, and TLS issues in widely used software.

    Visit blogRSSHN submissions
    SecurityOpen Source & Linux
    What HN says

    HN commenters call his posts brilliant, such as tricking Symantec with a fake private key, and cite his work on Owncloud and HTML mail risks.

    Stats for nerds
    37HN people shared it
    55linked in comments
    2.2Kstory points
    Apr 2024last shared
    2014people per year2024

    Top posts on HN

    1. 1
      #include </etc/shadow>
      2 people · 422 points · first shared 2019 · 121 comments on HN
    2. 2
      Comodo ships Adware Privdog worse than Superfish
      1 person · 274 points · first shared 2015 · 46 comments on HN
    3. 3
      About the supposed factoring of a 4096 bit RSA key
      4 people · 231 points · first shared 2015 · 33 comments on HN
    4. 4
      Please do not put IP addresses into DNS MX records
      1 person · 228 points · first shared 2021 · 176 comments on HN
    5. 5
      How I Tricked Symantec with a Fake Private Key
      2 people · 200 points · first shared 2017 · 38 comments on HN
    6. 6
      Pwncloud – Bad crypto in the Owncloud encryption module
      6 people · 180 points · first shared 2016 · 43 comments on HN
    7. 7
      Userdir URLs like https://example.org/~username/ are dangerous
      1 person · 155 points · first shared 2020 · 131 comments on HN
    8. 8
      How Heartbleed could've been found
      3 people · 146 points · first shared 2015 · 40 comments on HN
    9. 9
      LibreSSL on Gentoo
      2 people · 99 points · first shared 2014 · 17 comments on HN
    10. 10
      Don't Leave Coredumps on Web Servers
      1 person · 87 points · first shared 2017 · 32 comments on HN

    What HN people wrote when they linked it

    • chubotApr 2016

      I'm pretty impressed by ASAN (and MSAN, UBSAN, etc.) It catches uses after free trivially, as long as you have unit tests, which I always do.

      I wonder at the cost of these 2 strategies, for the huge legacy of C/C++ infrastructure we have:

      1) refactoring it to be testable, adding unit tests, adding test coverage automation, adding ASAN/MSAN builds, etc. (LLVM is a game changer IMO in addition to C++ 11; things have changed so much in the last 5 years)

      2) rewriting it in Rust

      I'm not claiming anything specific, but #2 seems strictly more expensive, since you still need unit tests for logic bugs anyway (and yes I have written OCaml and get that you can replace control flow with typed data, etc.) #1 also has a straightforward migration path.

      More to the point, most open source software has TERRIBLE test hygiene. If they don't even have time to write tests, I wonder how they will have time to rewrite in Rust.

      I'm all for new software in Rust, but I'm thinking about all of Linux user space, web servers, web browsers, every programming language implementation, etc.

      Also, fuzzing can be combined with ASAN.

      https://blog.hboeck.de/archives/868-How-Heartbleed-couldve-been-found.html

      Yes it would be better to know these things statically and not dynamically, and I'm glad that Rust has innovated in this space.

    • Anthony-GJun 2017

      Wikipedia has a good description on what OCSP Stapling is[1] and how it works. When I read the Apache projects' WONTFIX reason, I presumed that it was related to how plain OCSP requires the client to "phone home" in order to check whether a certificate has been revoked or not – which has implications for the privacy of the browser.

      However, now that I know OCSP Stapling works (the web server caches and proxies time-stamped OCSP responses that are signed by the CA), the Apache position is much less reasonable. As a Let’s Encrypt user, I “phone home” every couple of months to renew my X.509 key and certificate. That’s not a privacy concern for me or anyone else who happens to browse my site.

      I also found a good article by Hanno Böck[2] which provides more details on how OCSP Stapling is thoroughly broken on Apache as described by tialaramex).

      [1] https://en.wikipedia.org/wiki/OCSP_stapling

      [2] https://blog.hboeck.de/archives/886-The-Problem-with-OCSP-Stapling-and-Must-Staple-and-why-Certificate-Revocation-is-still-broken.html

    • masamune__Mar 2015

      Actually, libressl is practical drop-in replacement of openssl if you use only sane parts of openssl's functionality.

      Biggest problem now is some upstream softwares still depends on insanity Openbsd devs nuked away, like RAND_egd() or won't admit that libressl actually exist :)

      (https://devsonacid.wordpress.com/2014/07/12/how-compatible-is-libressl/, https://blog.hboeck.de/archives/851-LibreSSL-on-Gentoo.html)

      But situation is changing as more and more upstream developers abandon those APIs : https://github.com/gentoo/libressl/blob/master/README.md

      And I guess this is cool thing about libressl: even if it fails to replace openssl for real good, it is still forcing others to advance toward right direction (remember the linux fork fuss last year? You can disagree with me but I myself consider it linux's 'fault' not to have consistent mechanism of extracting entropy....it doesn't have to be arc4random but it could have been better in the first place if this IMO)

    • wfnMay 2015

      > Still think it was 'cosmic rays' on SKS's machines?

      Just FYI, this kind of stuff seems to have been done before, with vulnerable keys found:

      https://eprint.iacr.org/2012/064.pdf (2012),

      https://factorable.net/

      (these two are mentioned and linked to from https://blog.hboeck.de/archives/872-About-the-supposed-factoring-of-a-4096-bit-RSA-key.html)

      And (off-topic) if you are wondering why some of your recent comments are being downvoted so much, it's probably because of the tone (saying things such as "good job repeating my research" when work of the same kind with results of the same kind had been done before (see above.))

      Still an interesting result and curious re. SKS servers (not) checking subkeys etc...

      also https://news.ycombinator.com/item?id=9562170

    • bad_userDec 2019

      I don't even understand why people use antivirus software. Sure, if you're on an ancient version of your OS, like Windows XP, then it might serve some purpose, but assuming modern versions of these operating systems, antivirus software does more harm than good.

      Worried about browser extensions?

      Another problem is that popular antivirus software are also installing their own root certificate so they can MITM secure HTTPS connections.

      For example Bitdefender is able to inspect and modify your Google search result without installing a browser extension. And this is a common practice. See for example:

      https://blog.hboeck.de/archives/869-How-Kaspersky-makes-you-vulnerable-to-the-FREAK-attack-and-other-ways-Antivirus-software-lowers-your-HTTPS-security.html

    • mikemaccanaMar 2015

      Mike here using old openid account, as I'm replying too fast.

      The CA handles the verification, hence the difference in price. Symantec/Verisign is the most expensive, Digicert is in the middle, Comodo and the Symantec budget brands are the cheapest.

      As mentioned elsewhere, I do have code written against the Comodo API, and it would be a lot more profitable to use them. However I (and the tech companies I'm targeting, eg, Stripe, GitHub) use Digicert certs, mainly for reasons of verification speed but also business practice compared to competitors, eg, Comodo: https://blog.hboeck.de/archives/866-PrivDog-wants-to-protect-your-privacy-by-sending-data-home-in-clear-text.html

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