Bug #9644
closedssl hostname verification security bug: verify_certificate_identity wildcard matching allows to much
Description
Hi,
I'm not a ruby developer but the maintainer of the IO::Socket::SSL module in Perl. While comparing the state of the SSL implementations in various languages I've noticed, that your validation of the hostname inside the certificate is wrong regarding wildcards.
According to the RFC2818 (http) or RFC6125 (includes http and others) only the leftmost part of the name specification might contain a wildcard, e.g *.foo.bar
is allowed, but not www.*.foo.bar
or even www.*.*.*
. Unfortunatly the implementation of verify_certificate_identity
in openssl/ssl.rb (or openssl/ssl-internal.rb in older versions) does a global substitution of *
with [^.]+
and thus allows wildcards anywhere and also multiple wildcards. I've verified my assumption with a certificate for www.*.foo.*
, which got successfully verified against www.bar.foo.org
or www.foobar.foo.bar
on ruby 1.9.1. And, from looking at the code the current ruby version has the same problem.
Also, from reading the code I understand that you use the same hostname verification for SMTP, IMAP and POP too. But the verification schemes for these protocols differ from http (see RFC2595 for SMTP, RFC4642 for IMAP and POP):
- while http allows something like www*.example.com the other protocols only allow *.example.com, e.g. the the wildcard must fully replace the leftmost part of the hostname.
- while with http one should not check the common name if subject alternative names exist (and you've implemented it this way), with the other protocols one check common name too.
Regards,
Steffen
Files
Updated by nobu (Nobuyoshi Nakada) over 10 years ago
- Description updated (diff)
- Category set to ext/openssl
- Status changed from Open to Assigned
- Assignee set to MartinBosslet (Martin Bosslet)
- Priority changed from Normal to 5
- Target version set to 2.2.0
- Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN to 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED
Seems no wildcard tests.
Updated by hansdegraaff (Hans de Graaff) over 9 years ago
It looks like this is fixed with https://github.com/ruby/openssl/commit/e9a7bcb8bf2902f907c148a00bbcf21d3fa79596 which is related to https://bugzilla.redhat.com/show_bug.cgi?id=1209981
Updated by nagachika (Tomoyuki Chikanaga) over 9 years ago
- Status changed from Assigned to Closed
- % Done changed from 0 to 100
Applied in changeset r50292.
- ext/openssl/lib/openssl/ssl.rb: stricter hostname verification
following RFC 6125. with the patch provided by Tony Arcieri and
Hiroshi Nakamura [ruby-core:61545] [Bug #9644] - test/openssl/test_ssl.rb: add tests for above.
Updated by nagachika (Tomoyuki Chikanaga) over 9 years ago
- Backport changed from 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED to 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: DONE
Backported into ruby_2_2
branch at r50293.
Updated by usa (Usaku NAKAMURA) over 9 years ago
- Backport changed from 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: DONE to 1.9.3: REQUIRED, 2.0.0: DONE, 2.1: DONE
ruby_2_0_0 r50294 merged revision(s) 50292.
Updated by terceiro (Antonio Terceiro) over 9 years ago
- File CVE-2015-1855.patch CVE-2015-1855.patch added
Hi,
I was able to backport the patch to Ruby 1.9.3, and it will be included in a Debian wheezy security update soon. I am attaching the patch here.