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XML External Entity (XXE) Injection in OWSLib

High
tomkralidis published GHSA-8h9c-r582-mggc Mar 6, 2023

Package

pip OWSLib (pip)

Affected versions

< 0.28.1

Patched versions

0.28.1

Description

Impact

OWSLib's XML parser (which supports both lxml and xml.etree) does not disable entity resolution for lxml, and could lead to arbitrary file reads from an attacker-controlled XML payload. This affects all XML parsing in the codebase.

Patches

  • Use only lxml for XML handling, adding resolve_entities=False to lxml's parser: #863

Workarounds

patch_well_known_namespaces(etree)
etree.set_default_parser(
    parser=etree.XMLParser(resolve_entities=False)
)

References

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

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:H/I:N/A:L

CVE ID

CVE-2023-27476

Weaknesses

Credits