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XML external entity (XXE) processing ('external-parameter-entities' feature was not fully disabled))

Moderate severity GitHub Reviewed Published Jan 31, 2020 in checkstyle/checkstyle • Updated Jan 9, 2023

Package

maven com.puppycrawl.tools:checkstyle (Maven)

Affected versions

< 8.29

Patched versions

8.29

Description

Due to an incomplete fix for CVE-2019-9658, checkstyle was still vulnerable to XML External Entity (XXE) Processing.

Impact

User: Build Maintainers

This vulnerability probably doesn't impact Maven/Gradle users as, in most cases, these builds are processing files that are trusted, or pre-vetted by a pull request reviewer before being run on internal CI infrastructure.

User: Static Analysis as a Service

If you operate a site/service that parses "untrusted" Checkstyle XML configuration files, you are vulnerable to this and should patch.

Note from the discoverer of the original CVE-2019-9658:

While looking at a few companies that run Checkstyle/PMD/ect... as a service I notice that it's a common pattern to run the static code analysis tool inside of a Docker container with the following flags:

--net=none \
--privileged=false \
--cap-drop=ALL

Running the analysis in Docker has the advantage that there should be no sensitive local file information that XXE can exfiltrate from the container. Additionally, these flags prevent vulnerabilities in static analysis tools like Checkstyle from being used to exfiltrate data via XXE or to perform SSRF.
- Jonathan Leitschuh

Patches

Has the problem been patched? What versions should users upgrade to?

Patched, will be released with version 8.29 at 26 Jan 2020.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

No workaround are available

References

For more information

If you have any questions or comments about this advisory:

References

@romani romani published to checkstyle/checkstyle Jan 31, 2020
Reviewed Jan 31, 2020
Published to the GitHub Advisory Database Jan 31, 2020
Last updated Jan 9, 2023

Severity

Moderate

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
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS score

0.311%
(70th percentile)

Weaknesses

CVE ID

CVE-2019-10782

GHSA ID

GHSA-763g-fqq7-48wg

Source code

No known source code

Credits

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