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How the Mentioned CVE Works
The vulnerability resides in the `excerpt-include` macro, a feature designed to embed content from one page into another. The core of the issue lies in improper input sanitization. Specifically, when the `excerpt-include` macro processes a page to be included, it fails to escape the of that included page. This oversight occurs at a critical point in the code, specifically within `ExcerptInclude.xml` at line 277.
An attacker who can edit a page can exploit this by setting a malicious page . Because the is not escaped, it is interpreted not as plain text, but as executable XWiki syntax. An attacker can inject a payload like `{{async}}{{groovy}}…{{/groovy}}{{/async}}` directly into the page . When the `excerpt-include` macro renders the page, it executes this injected syntax with the macro’s own rights.
The situation is further exacerbated by how the macro handles the content of the excerpt itself. The content of the `excerpt` macro is rendered and then outputted into the macro’s content. This means any malicious syntax placed inside the excerpt is also executed with the macro’s privileges. This combination of vulnerabilities—unescaped s and un-sanitized excerpt content—creates a powerful vector for remote code execution (RCE). Any user with edit permissions on any page can leverage this to execute arbitrary Groovy code on the server.
DailyCVE Form:
Platform: XWiki Platform
Version: Versions with `excerpt-include` macro (pre-patch)
Vulnerability: XWiki Syntax Injection → RCE
Severity: Critical
Date: 2024-06-24
Prediction: Patch expected in XWiki 15.0 RC1
What Undercode Say: Analytics
The vulnerability is triggered when a page with a malicious is included. The following steps and code snippets demonstrate the exploitation:
1. Create a Page: As a regular user, create a new page named “Exploit”.
2. Set Malicious In the edit screen, change the page’s to the following payload:
{{async}}{{groovy}}println("Hello from Groovy !"){{/groovy}}{{/async}}
3. Craft the Content: Set the page’s content to:
{{excerpt-include 0="Exploit.WebHome"}}{{/excerpt-include}}
{{excerpt}}
{{async}}{{groovy}}println("Hello from Groovy content!"){{/groovy}}{{/async}}
{{/excerpt}}
4. Execute: Save and view the page.
Successful Exploitation: If the page displays “Hello from Groovy !” without the surrounding macro code, or “Hello from Groovy content!”, it confirms the attack succeeded.
Exploit
The exploit leverages the `excerpt-include` macro’s failure to sanitize input. By injecting Groovy code into the page or the `excerpt` content, an attacker can execute arbitrary code on the server. The core of the exploit is the injection point:
{{async}}{{groovy}}[Malicious Code]{{/groovy}}{{/async}}
This payload, when placed in the or excerpt, is executed with the macro’s rights, leading to full remote code execution.
Protection
- Immediate Action: Upgrade to XWiki 15.0 RC1 or a later version that includes the security patch.
- Workaround: If an immediate upgrade is not possible, restrict edit permissions on all pages to only trusted users. This limits the attack surface by preventing untrusted users from injecting malicious s or content.
Impact
Successful exploitation allows a malicious user to execute arbitrary code on the XWiki server. This has a critical impact on:
– Confidentiality: An attacker can read any data stored on the wiki.
– Integrity: An attacker can modify or delete any content or configuration.
– Availability: An attacker can disrupt or completely take down the XWiki service.
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Sources:
Reported By: github.com
Extra Source Hub:
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