Medium: ruby21

Issue Overview:

RubyGems provides the ability of a domain to direct clients to a separate host that is used to fetch gems and make API calls against. This mechanism is implemented via DNS, specificly a SRV record _rubygems._tcp under the original requested domain. RubyGems did not validate the hostname returned in the SRV record before sending requests to it. (CVE-2015-3900)

As discussed upstream (https://www.trustwave.com/Resources/Security-Advisories/Advisories/TWSL2015-009/?fid=6478), CVE-2015-4020 is due to an incomplete fix for CVE-2015-3900, which allowed redirection to an arbitrary gem server in any security domain.

Affected Packages:

ruby21

Issue Correction:
Run yum update ruby21 to update your system.

New Packages:

i686:  
    ruby21-devel-2.1.6-1.17.amzn1.i686  
    ruby21-libs-2.1.6-1.17.amzn1.i686  
    ruby21-2.1.6-1.17.amzn1.i686  
    rubygem21-bigdecimal-1.2.4-1.17.amzn1.i686  
    rubygem21-io-console-0.4.3-1.17.amzn1.i686  
    ruby21-debuginfo-2.1.6-1.17.amzn1.i686  
    rubygem21-psych-2.0.5-1.17.amzn1.i686  
  
noarch:  
    rubygems21-2.2.3-1.17.amzn1.noarch  
    rubygems21-devel-2.2.3-1.17.amzn1.noarch  
    ruby21-doc-2.1.6-1.17.amzn1.noarch  
    ruby21-irb-2.1.6-1.17.amzn1.noarch  
  
src:  
    ruby21-2.1.6-1.17.amzn1.src  
  
x86_64:  
    ruby21-libs-2.1.6-1.17.amzn1.x86_64  
    rubygem21-bigdecimal-1.2.4-1.17.amzn1.x86_64  
    ruby21-debuginfo-2.1.6-1.17.amzn1.x86_64  
    ruby21-devel-2.1.6-1.17.amzn1.x86_64  
    rubygem21-psych-2.0.5-1.17.amzn1.x86_64  
    ruby21-2.1.6-1.17.amzn1.x86_64  
    rubygem21-io-console-0.4.3-1.17.amzn1.x86_64  

Additional References

Red Hat: CVE-2015-3900, CVE-2015-4020

Mitre: CVE-2015-3900, CVE-2015-4020