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DDFFileParser is vulnerable to XXE Attacks.

Moderate
sbernard31 published GHSA-wc9j-gc65-3cm7 Aug 31, 2023

Package

maven org.eclipse.leshan:leshan-core (Maven)

Affected versions

<=1.4.2
>= 2.0.0-M1, < 2.0.0-M13

Patched versions

1.5.0
2.0.0-M13

Description

Impact

DDFFileParser and DefaultDDFFileValidator (and so ObjectLoader) are vulnerable to XXE Attacks.

DDF file is a LWM2M format used to store LWM2M object description.
Leshan users are impacted only if they parse untrusted DDF files (e.g. if they let external users provide their own model), in that case they MUST upgrade to fixed version.
If you parse only trusted DDF file and validate only with trusted xml schema, upgrading is not mandatory.

Patches

This is fixed in v1.5.0 and 2.0.0-M13.

Workarounds

No easy way. Eventually writing your own DDFFileParser/DefaultDDFFileValidator (and so ObjectLoader) creating a DocumentBuilderFactory with :

// For DDFFileParser
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true); // Disable DTDs
factory.setXIncludeAware(false); // Disable XML Inclusions
factory.setExpandEntityReferences(false); // disable expand entity reference nodes

// For DefaultDDFFileValidator
SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
factory.setProperty(XMLConstants.ACCESS_EXTERNAL_DTD, "");
factory.setProperty(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");

References

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
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
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:H/PR:N/UI:N/S:U/C:H/I:L/A:N

CVE ID

CVE-2023-41034

Weaknesses

Credits