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Privilege escalation (PR) from user registration through PDFClass

Critical
surli published GHSA-vxwr-wpjv-qjq7 Apr 10, 2024

Package

maven org.xwiki.platform:xwiki-platform-oldcore (Maven)

Affected versions

>= 3.0.1, < 14.10.19
>= 15.0-rc-1, < 15.5.4
>= 15.6-rc-1, < 15.9

Patched versions

14.10.19
15.5.4
15.9

Description

Impact

Remote code execution is possible via PDF export templates.
To reproduce on an installation, register a new user account with username PDFClass if XWiki.PDFClass does not exist.
On XWiki.PDFClass, use the class editor to add a "style" property of type "TextArea" and content type "Plain Text".
Then, add an object of class PDFClass and set the "style" attribute to $services.logging.getLogger('PDFClass').error("I got programming: $services.security.authorization.hasAccess('programming')").
Finally, go to <host>/xwiki/bin/export/Main/WebHome?format=pdf&pdftemplate=XWiki.PDFClass. If the logs contain "ERROR PDFClass - I got programming: true", the instance is vulnerable.

Patches

This vulnerability has been patched in XWiki 14.10.20, 15.5.4 and 15.10-rc-1.

Workarounds

If PDF templates are not typically used on the instance, an administrator can create the document XWiki.PDFClass and block its edition, after making sure that it does not contain a style attribute.
Otherwise, the instance needs to be updated.

References

Severity

Critical

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
Low
User interaction
None
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:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVE ID

CVE-2024-31981

Weaknesses