ESB-2018.0506 - [Win][UNIX/Linux] RubyGems: Execute arbitrary code/commands - Existing account 2018-02-20

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             AUSCERT External Security Bulletin Redistribution

                         RubyGems security updates
                             20 February 2018


        AusCERT Security Bulletin Summary

Product:           RubyGems
Operating System:  UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Cross-site Scripting            -- Existing Account
                   Access Confidential Data        -- Existing Account
                   Reduced Security                -- Existing Account
Resolution:        Patch/Upgrade

Original Bulletin:

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Multiple vulnerabilities in RubyGems

Posted by usa on 17 Feb 2018

There are multiple vulnerabilities in RubyGems bundled by Ruby. It is reported 
at the official blog of RubyGems.


The following vulnerabilities have been reported.

    Prevent path traversal when writing to a symlinked basedir outside of the root.
    Fix possible Unsafe Object Deserialization Vulnerability in gem owner.
    Strictly interpret octal fields in tar headers.
    Raise a security error when there are duplicate files in a package.
    Enforce URL validation on spec homepage attribute.
    Mitigate XSS vulnerability in homepage attribute when displayed via gem server.
    Prevent Path Traversal issue during gem installation.

It is strongly recommended for Ruby users to take one of the following workarounds 
as soon as possible.

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
    prior to trunk revision 62422


RubyGems 2.7.6 or later includes the fix for the vulnerabilities, so upgrade 
RubyGems to the latest version.

gem update --system

If you can’t upgrade RubyGems, you can apply the following patches as a workaround.

    for Ruby 2.2.9
    for Ruby 2.3.6
    for Ruby 2.4.3
    for Ruby 2.5.0

About the trunk, update to the latest revision.

This report is based on the official blog of RubyGems.

    Originally published at 2018-02-17 03:00:00 UTC

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