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Remote Code Execution (RCE) vulnerability in dropwizard-validation

High severity GitHub Reviewed Published Apr 9, 2020 in dropwizard/dropwizard • Updated Jan 9, 2023

Package

maven io.dropwizard:dropwizard-validation (Maven)

Affected versions

< 1.3.21
>= 2.0.0, < 2.0.3

Patched versions

1.3.21
2.0.3

Description

Summary

A server-side template injection was identified in the self-validating (@SelfValidating) 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), 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/CVE-2020-5245) unfortunately didn't fix the underlying issue completely.

Impact

This 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) expressions when using the self-validating feature (@SelfValidating, @SelfValidation) in dropwizard-validation.

Patches

The 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, it has to be explicitly allowed by setting SelfValidating#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:

Workarounds

If you are not able to upgrade to one of the aforementioned versions of dropwizard-validation but still want to use the @SelfValidating feature, make sure to properly sanitize any message you're adding to the ViolationCollector in the method annotated with @SelfValidation.

Example:

@SelfValidation
public void validateFullName(ViolationCollector col) {
    if (fullName.contains("_")) {
        // Sanitize fullName variable by escaping relevant characters such as "$"
        col.addViolation("Full name contains invalid characters:  " + sanitizeJavaEl(fullName));
    }
}

See also:
https://github.com/dropwizard/dropwizard/blob/v2.0.3/dropwizard-validation/src/main/java/io/dropwizard/validation/InterpolationHelper.java

References

For more information

If you have any questions or comments about this advisory:

Security contact

If 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#reporting-a-vulnerability

References

@joschi joschi published to dropwizard/dropwizard Apr 9, 2020
Reviewed Apr 10, 2020
Published to the GitHub Advisory Database Apr 10, 2020
Last updated Jan 9, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H

EPSS score

4.708%
(93rd percentile)

Weaknesses

CVE ID

CVE-2020-11002

GHSA ID

GHSA-8jpx-m2wh-2v34

Source code

No known source code

Credits

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