GHSA-8jpx-m2wh-2v34: Remote Code Execution (RCE) vulnerability in dropwizard-validation
SummaryA server-side template injection was identified in the self-validating ([`@SelfValidating`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/SelfValidating.html)) feature of **dropwizard-validation** enabling attackers to inject arbitrary Java EL expressions, leading to Remote Code Execution (RCE) vulnerability.If you're using a self-validating bean (via [`@SelfValidating`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/SelfValidating.html)), an upgrade to Dropwizard 1.3.21/2.0.3 or later is strongly recommended.The changes introduced in Dropwizard 1.3.19 and 2.0.2 (see [GHSA-3mcp-9wr4-cjqf](https://github.com/dropwizard/dropwizard/security/advisories/GHSA-3mcp-9wr4-cjqf)/[CVE-2020-5245](https://github.com/advisories/GHSA-3mcp-9wr4-cjqf)) unfortunately didn't fix the underlying issue completely.ImpactThis issue may allow Remote Code Execution (RCE), allowing to run arbitrary code on the host system (with the privileges of the Dropwizard service account privileges) by injecting arbitrary [Java Expression Language (EL)](https://docs.jboss.org/hibernate/validator/6.1/reference/en-US/html_single/#section-interpolation-with-message-expressions) expressions when using the self-validating feature ([`@SelfValidating`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/SelfValidating.html), [`@SelfValidation`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/SelfValidation.html)) in **dropwizard-validation**.PatchesThe issue has been fixed in **dropwizard-validation** **1.3.21** and **2.0.3** or later. We strongly recommend upgrading to one of these versions.The evaluation of EL expressions has been disabled by default now.In order to use some interpolation in the violation messages added to [`ViolationCollector`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/ViolationCollector.html), it has to be explicitly allowed by setting [`SelfValidating#escapeExpressions()`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/SelfValidating.html#escapeExpressions--) to `false`.It is also recommended to use the `addViolation` methods supporting message parameters instead of EL expressions introduced in Dropwizard 1.3.21 and 2.0.3:[`ViolationCollector#addViolation(String, Map<String, Object>`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/ViolationCollector.html#addViolation-java.lang.String-java.util.Map-)[`ViolationCollector#addViolation(String, String, Map<String, Object>`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/ViolationCollector.html#addViolation-java.lang.String-java.lang.String-java.util.Map-)[`ViolationCollector#addViolation(String, String, Integer, Map<String, Object>`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/ViolationCollector.html#addViolation-java.lang.String-java.lang.Integer-java.lang.String-java.util.Map-)[`ViolationCollector#addViolation(String, String, String, Map<String, Object>`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/ViolationCollector.html#addViolation-java.lang.String-java.lang.String-java.lang.String-java.util.Map-)WorkaroundsIf you are not able to upgrade to one of the aforementioned versions of **dropwizard-validation** but still want to use the [`@SelfValidating`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.2/io/dropwizard/validation/selfvalidating/SelfValidating.html) feature, make sure to properly sanitize any message you're adding to the [`ViolationCollector`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/ViolationCollector.html) in the method annotated with [`@SelfValidation`](https://javadoc.io/static/io.dropwizard/dropwizard-project/2.0.3/io/dropwizard/validation/selfvalidating/SelfValidation.html).Example:See also:
https://github.com/dropwizard/dropwizard/blob/v2.0.3/dropwizard-validation/src/main/java/io/dropwizard/validation/InterpolationHelper.javaReferenceshttps://github.com/dropwizard/dropwizard/security/advisories/GHSA-3mcp-9wr4-cjqfhttps://github.com/dropwizard/dropwizard/pull/3208https://github.com/dropwizard/dropwizard/pull/3209https://docs.jboss.org/hibernate/validator/6.1/reference/en-US/html_single/#section-hibernateconstraintvalidatorcontextFor more informationIf you have any questions or comments about this advisory:Open an issue in [dropwizard/dropwizard](https://github.com/dropwizard/dropwizard/issues/new)Start a discussion on the [dropwizard-dev mailing list](https://groups.google.com/forum/#!forum/dropwizard-dev)Security contactIf you want to responsibly disclose a security issue in Dropwizard or one of its official modules, please contact us via the published channels in our [security policy](https://github.com/dropwizard/dropwizard/security/policy):https://github.com/dropwizard/dropwizard/security/policy#reporting-a-vulnerability
CVSS v3.1: 8