Date: Sun, 6 Dec 2020 14:21:31 +1000 From: Paul King <paulk@...che.org> To: oss-security@...ts.openwall.com Subject: [CVE-2020-17521]: Apache Groovy Information Disclosure 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 Impact: 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 stores executable code in the resulting temporary directory, then the risk is high, since this can lead to local privilege escalation. If such Groovy code is making use of the temporary directory to store sensitive information, then the risk is medium, 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 to local 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. Description: 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. 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 whereby executables or information could be modified, but still leaves the potential for sensitive information leakage. Groovy 2.4/JDK 6 users are recommended to use the `java.io.tmpdir` mitigation. 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. Credit: This vulnerability was discovered by Jonathan Leitschuh ( https://twitter.com/jlleitschuh) Similar Vulnerabilities: * Jetty - https://github.com/eclipse/jetty.project/security/advisories/GHSA-g3wg-6mcf-8jj6 * JUnit4 - https://github.com/junit-team/junit4/security/advisories/GHSA-269g-pwp5-87pp * Google Guava - https://github.com/google/guava/issues/4011 * Apache Ant - https://nvd.nist.gov/vuln/detail/CVE-2020-1945 * JetBrains Kotlin Compiler - https://nvd.nist.gov/vuln/detail/CVE-2020-15824 References:  CWE-379: Creation of Temporary File in Directory with Insecure Permissions (https://cwe.mitre.org/data/definitions/379.html)  "File.createTempFile" should not be used to create a directory ( https://rules.sonarsource.com/java/tag/owasp/RSPEC-2976)  Groovy CVE list (https://groovy-lang.org/security.html)  https://docs.groovy-lang.org/latest/html/groovy-jdk/java/io/File.html#createTempDir()  https://docs.groovy-lang.org/latest/html/groovy-jdk/java/io/File.html#createTempDir(java.lang.String,%20java.lang.String)  related Jira issue: https://issues.apache.org/jira/browse/GROOVY-9824
Powered by blists - more mailing lists
Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.