Bug 1561950 (CVE-2018-8777)

Summary: CVE-2018-8777 ruby: DoS by large request in WEBrick
Product: [Other] Security Response Reporter: Adam Mariš <amaris>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bkearney, cbillett, cbuissar, ccoleman, cpelland, dajohnso, dedgar, dmcphers, gblomqui, gmccullo, gtanzill, hhorak, hhudgeon, jaruga, jfrey, jgoulding, jhardy, jorton, jprause, mtasaka, obarenbo, pvalena, roliveri, ruby-maint, simaishi, s, strzibny, tomckay, vanmeeuwen+fedora, vondruch
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=moderate,public=20180328,reported=20180329,source=internet,cvss3=7.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H,cwe=CWE-400,rhel-5/ruby=wontfix,rhel-6/ruby=wontfix,rhel-7/ruby=affected,rhel-8/ruby=notaffected,cfme-5/rh-ruby22-ruby=affected,cfme-5/ruby-200-ruby=affected,rhscl-3/rh-ruby23-ruby=affected,rhscl-3/rh-ruby22-ruby=wontfix,rhscl-3/rh-ruby24-ruby=affected,rhscl-3/rh-ruby25-ruby=affected,sam-1/ruby193-ruby=wontfix,openshift-1/ruby193-ruby=affected,fedora-all/ruby=affected
Fixed In Version: ruby 2.2.10, ruby 2.3.7, ruby 2.4.4, ruby 2.5.1 Doc Type: If docs needed, set a value
Doc Text:
It was found that WEBrick could be forced to use an excessive amount of memory during the processing of HTTP requests, leading to a Denial of Service. An attacker could use this flaw to send huge requests to a WEBrick application, resulting in the server running out of memory.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 1568430, 1651798, 1652037, 1652038, 1561956, 1561957, 1561958, 1563873, 1563874, 1565258, 1568428, 1568429, 1568431, 1568432    
Bug Blocks: 1561954    

Description Adam Mariš 2018-03-29 09:08:24 UTC
If an attacker sends a large request which contains huge HTTP headers, WEBrick try to process it on memory, so the request causes the out-of-memory DoS attack.

Affected versions:

Ruby 2.2 series: 2.2.9 and earlier
Ruby 2.3 series: 2.3.6 and earlier
Ruby 2.4 series: 2.4.3 and earlier
Ruby 2.5 series: 2.5.0 and earlier

External References:

https://www.ruby-lang.org/en/news/2018/03/28/large-request-dos-in-webrick-cve-2018-8777/

Comment 1 Adam Mariš 2018-03-29 09:14:13 UTC
Created ruby tracking bugs for this issue:

Affects: fedora-all [bug 1561957]

Comment 8 Andrej Nemec 2018-05-14 15:26:26 UTC
Statement:

This issue affects the versions of ruby as shipped with Red Hat CloudForms 4. Red Hat Product Security has rated this issue as having security impact of Moderate. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

This issue affects the versions of ruby as shipped with Red Hat Subscription Asset Manager 1. Red Hat Product Security has rated this issue as having security impact of Moderate. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Comment 9 Jun Aruga 2018-11-15 18:37:13 UTC
Upstream patch:

> Affected versions:

trunk branch: r62965
https://github.com/ruby/ruby/commit/32e277acbf35de454befc1573aff1063a55403cf

> Ruby 2.2 series: 2.2.9 and earlier

ruby_2_2 branch
https://github.com/ruby/ruby/commit/a45622669bb1ff18d3ee9b411128acd839c4263e

> Ruby 2.3 series: 2.3.6 and earlier
> Ruby 2.4 series: 2.4.3 and earlier
> Ruby 2.5 series: 2.5.0 and earlier

On ruby_2_N branches, search by "webrick/httpauth/digestauth: stream req.body" or "r62965".

Notable comment in the commit.

> WARNING! WARNING! WARNING!  LIKELY BROKEN CHANGE
> 
> Pass a proc to WEBrick::HTTPRequest#body to avoid reading a
> potentially large request body into memory during
> authentication.
> 
> WARNING! this will break apps completely which want to do
> something with the body besides calculating the MD5 digest
of it.
> 
> Also, keep in mind that probably nobody uses "auth-int".
> Servers such as Apache, lighttpd, nginx don't seem to
> support it; nor does curl when using POST/PUT bodies;
> and we didn't have tests for it until now...

Comment 10 Jun Aruga 2018-11-16 16:53:28 UTC
> trunk branch: r62965

but ruby_2_2 branch's commit is merged from between r62960 and r62965 with new tests.
https://github.com/ruby/ruby/commit/a45622669bb1ff18d3ee9b411128acd839c4263e
It looks better to merge the commit on ruby_2_2.

Comment 11 Vít Ondruch 2018-11-20 11:47:16 UTC
(In reply to Jun Aruga from comment #9)
> > Also, keep in mind that probably nobody uses "auth-int".
> > Servers such as Apache, lighttpd, nginx don't seem to
> > support it; nor does curl when using POST/PUT bodies;
> > and we didn't have tests for it until now...

I think this ^^ comment explains, that this is probably corner case, which won't affect too many people. Also, upstream applied the patch at the end, even there was this concern, so let's follow.

Comment 14 errata-xmlrpc 2018-11-29 09:56:39 UTC
This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 6
  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS

Via RHSA-2018:3729 https://access.redhat.com/errata/RHSA-2018:3729

Comment 15 errata-xmlrpc 2018-11-29 10:11:20 UTC
This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 6
  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS

Via RHSA-2018:3730 https://access.redhat.com/errata/RHSA-2018:3730

Comment 16 errata-xmlrpc 2018-11-29 10:22:31 UTC
This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS

Via RHSA-2018:3731 https://access.redhat.com/errata/RHSA-2018:3731