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  1. Groovy
  2. GROOVY-9824

CVE-2020-17521 Apache Groovy Information Disclosure



    • Bug
    • Status: Closed
    • Major
    • Resolution: Fixed
    • None
    • 2.4.21, 2.5.14, 3.0.7, 4.0.0-alpha-2
    • None
    • None


      CVE-2020-17521 Apache Groovy Information Disclosure

      Severity: Important

      Vendor: The Apache Software Foundation

      Versions Affected:

      Unsupported Codehaus versions of Groovy from 2.0 to 2.4.4.
      Apache Groovy versions 2.4.4 to 2.4.20, 2.5.0 to 2.5.13,
      3.0.0 to 3.0.6, and 4.0.0-alpha-1.

      Fixed in versions 2.4.21, 2.5.14, 3.0.7, 4.0.0-alpha-2


      This vulnerability potentially impacts Unix-like systems, and very old
      versions of Mac OSX and Windows. On such OS versions, Groovy may create
      temporary directories within the OS temporary directory which is shared
      between all users on affected systems. Groovy will create such directories
      for internal use when producing Java Stubs (very low impact) or on behalf
      of user code via two extension methods[4,5] for creating temporary directories.
      If Groovy user code uses either of these extension methods, and storesexecutable code in the resulting temporary directory, then the risk is high,since this can lead to local privilege escalation. If such Groovy code is makinguse of the temporary directory to store sensitive information, then the risk ismedium, since such information could be exposed or modified.
      When analyzing the impact of this vulnerability, here are the important
      questions to ask:

      Is the Groovy code running on a machine with an impacted operating system?
      Do other users have access to the machine running the Groovy code?
      Does the Groovy code create temporary directories using Groovy's
      createTempDir extension methods[4,5]?

      If you answer no to any of these questions, you are not affected.
      If you answered yes, does the Groovy code write or store executable code
      in the temporary directory? If you answer yes, the risk is high, and can lead tolocal privilege escalation. Does the Groovy code write sensitive information,like API keys or passwords, into the temporary directory? If you answer yes,the risk is medium, and information may be exposed or modified.


      Groovy was making use of a method in the JDK which is now flagged as not
      suitable for security-sensitive contexts. In addition, Groovy wasn't checking
      a flag related to successful creation of the temporary directory which leads
      to a race condition whereby the vulnerability exists[1].

      For the fixed versions, Groovy 2.5 and above is now using a newer JDK method
      which creates a directory that is only readable by the user running the Groovy
      code. The same is true for the fixed Groovy 2.4 version except if running
      on a pre-JDK7 version of the JDK in which case a fallback implementation is
      used which now checks for successful creation of the temporary directory.
      This eliminates the high-risk scenario involving the race condition wherebyexecutables or information could be modified, but still leaves the potentialfor sensitive information leakage. Groovy 2.4/JDK 6 users are recommendedto use the `java.io.tmpdir` mitigation.


      Setting the `java.io.tmpdir` system environment variable to a directory
      that is exclusively owned by the executing user will fix this vulnerability
      for all operating systems and all Groovy versions.

      Users who cannot easily move to the fixed Groovy versions may wish to
      consider using the JDK's Files#createTempDirectory method instead of the
      Groovy extension methods.


      This vulnerability was discovered by Jonathan Leitschuh (https://twitter.com/jlleitschuh)

      Similar Vulnerabilities:


      [1] CWE-379: Creation of Temporary File in Directory with Insecure Permissions (https://cwe.mitre.org/data/definitions/379.html)
      [2] "File.createTempFile" should not be used to create a directory (https://rules.sonarsource.com/java/tag/owasp/RSPEC-2976)
      [3] Groovy CVE list (https://groovy-lang.org/security.html)
      [4] https://docs.groovy-lang.org/latest/html/groovy-jdk/java/io/File.html#createTempDir()
      [5] https://docs.groovy-lang.org/latest/html/groovy-jdk/java/io/File.html#createTempDir(java.lang.String,%20java.lang.String)




            paulk Paul King
            paulk Paul King
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