Ruby: Execute Arbitrary Code/Commands -- Remote with User Interaction

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.1496
                 A command injection vulnerability in RDoc
                                3 May 2021

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Ruby
Publisher:         Ruby
Operating System:  UNIX variants (UNIX, Linux, OSX)
                   Windows
Impact/Access:     Execute Arbitrary Code/Commands -- Remote with User Interaction
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-31799  

Original Bulletin: 
   https://www.ruby-lang.org/en/news/2021/05/02/os-command-injection-in-rdoc/

Comment: This advisory references vulnerabilities in products which run on 
         different platforms. It is recommended that administrators 
         running Ruby check for an updated version of the software for their
         operating system.

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CVE-2021-31799: A command injection vulnerability in RDoc

Posted by aycabta on 2 May 2021

There is a vulnerability about Command Injection in RDoc which is bundled in
Ruby. It is recommended that all Ruby users update RDoc to the latest version
that fixes this issue.

Details

The following vulnerability has been reported.

  o CVE-2021-31799

RDoc used to call Kernel#open to open a local file. If a Ruby project has a
file whose name starts with | and ends with tags , the command following the
pipe character is executed. A malicious Ruby project could exploit it to run an
arbitrary command execution against a user who attempts to run rdoc command.

Ruby users whose version of RDoc is affected by this issue should update to the
latest version of RDoc.

Affected Versions

  o All releases of RDoc from 3.11 to 6.3.0

How to Update

Run the following command to update RDoc to the latest version (6.3.1 or later)
to fix the vulnerability.

gem install rdoc

Credits

Thanks to Alexandr Savca for reporting the issue.

History

  o Originally published at 2021-05-02 09:00:00 UTC

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