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Missing escaping of { in Velocity escapetool allows remote code execution

Critical
michitux published GHSA-hf43-47q4-fhq5 Apr 10, 2024

Package

maven org.xwiki.commons:xwiki-commons-velocity (Maven)

Affected versions

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

Patched versions

14.10.19
15.5.4
15.9-rc-1

Description

Impact

The HTML escaping of escaping tool that is used in XWiki doesn't escape {, which, when used in certain places, allows XWiki syntax injection and thereby remote code execution.

To reproduce in an XWiki installation, open <xwiki-host>/xwiki/bin/view/Panels/PanelLayoutUpdate?place=%7B%7B%2Fhtml%7D%7D%7B%7Basync%20async%3Dfalse%7D%7D%7B%7Bvelocity%7D%7D%23evaluate(%24request.eval)%7B%7B%2Fvelocity%7D%7D%7B%7B%2Fasync%7D%7D&eval=Hello%20from%20URL%20Parameter!%20I%20got%20programming%3A%20%24services.security.authorization.hasAccess(%27programming%27) where <xwiki-host> is the URL of your XWiki installation. If this displays You are not admin on this place Hello from URL Parameter! I got programming: true, the installation is vulnerable.

Patches

The vulnerability has been fixed on XWiki 14.10.19, 15.5.5, and 15.9 RC1.

Workarounds

Apart from upgrading, there is no generic workaround. However, replacing $escapetool.html by $escapetool.xml in XWiki documents fixes the vulnerability. In a standard XWiki installation, we're only aware of the document Panels.PanelLayoutUpdate that exposes this vulnerability, patching this document is thus a workaround. Any extension could expose this vulnerability and might thus require patching, too.

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
None
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:N/UI:N/S:C/C:H/I:H/A:H

CVE ID

CVE-2024-31996

Weaknesses