From: Peter Todd <pete@petertodd•org>
To: cryptography@metzdowd•com, bitcoin-dev@lists•linuxfoundation.org
Subject: [bitcoin-dev] SHA1 collisions make Git vulnerable to attakcs by third-parties, not just repo maintainers
Date: Thu, 23 Feb 2017 13:14:09 -0500 [thread overview]
Message-ID: <20170223181409.GA6085@savin.petertodd.org> (raw)
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Worth noting: the impact of the SHA1 collison attack on Git is *not* limited
only to maintainers making maliciously colliding Git commits, but also
third-party's submitting pull-reqs containing commits, trees, and especially
files for which collisions have been found. This is likely to be exploitable in
practice with binary files, as reviewers aren't going to necessarily notice
garbage at the end of a file needed for the attack; if the attack can be
extended to constricted character sets like unicode or ASCII, we're in trouble
in general.
Concretely, I could prepare a pair of files with the same SHA1 hash, taking
into account the header that Git prepends when hashing files. I'd then submit
that pull-req to a project with the "clean" version of that file. Once the
maintainer merges my pull-req, possibly PGP signing the git commit, I then take
that signature and distribute the same repo, but with the "clean" version
replaced by the malicious version of the file.
--
https://petertodd.org 'peter'[:-1]@petertodd.org
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next reply other threads:[~2017-02-23 18:14 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-23 18:14 Peter Todd [this message]
2017-02-23 21:28 ` Peter Todd
2017-02-23 23:57 ` Aymeric Vitte
2017-02-24 10:04 ` Tim Ruffing
2017-02-24 15:18 ` Aymeric Vitte
2017-02-24 16:30 ` Tim Ruffing
2017-02-24 17:29 ` Aymeric Vitte
[not found] <mailman.22137.1487974823.31141.bitcoin-dev@lists.linuxfoundation.org>
2017-02-24 23:49 ` Steve Davis
2017-02-25 1:01 ` Peter Todd
2017-02-25 12:04 ` Steve Davis
2017-02-25 14:50 ` Leandro Coutinho
2017-02-25 16:10 ` Ethan Heilman
2017-02-25 17:45 ` Shin'ichiro Matsuo
2017-02-27 9:15 ` Henning Kopp
2017-02-25 18:19 ` Alice Wonder
2017-02-25 18:36 ` Ethan Heilman
2017-02-25 19:12 ` Peter Todd
2017-02-25 20:42 ` Watson Ladd
2017-02-25 20:57 ` Peter Todd
2017-02-25 20:53 ` Russell O'Connor
2017-02-25 21:04 ` Peter Todd
2017-02-25 21:21 ` Dave Scotese
2017-02-25 21:34 ` Steve Davis
2017-02-25 21:40 ` Peter Todd
2017-02-25 21:54 ` Steve Davis
2017-02-25 22:14 ` Pieter Wuille
2017-02-25 22:34 ` Ethan Heilman
2017-02-26 6:26 ` Steve Davis
2017-02-26 6:36 ` Pieter Wuille
2017-02-26 7:16 ` Steve Davis
[not found] ` <CAPg+sBirowtHqUT5GUJf9hmDEACKVX19HAon-rrz7GmO8OBsNg@mail.gmail.com>
2017-02-26 16:53 ` Steve Davis
2017-02-25 23:09 ` Leandro Coutinho
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