XWiki 14.x RCE via HTML Sanitizer allowing form/input tags
CVE-2023-36471 Published on June 29, 2023
HTML sanitizer allows form elements in restricted in org.xwiki.commons:xwiki-commons-xml
Xwiki commons is the common modules used by other XWiki top level projects. The HTML sanitizer that is included in XWiki since version 14.6RC1 allowed form and input HTML tags. In the context of XWiki, this allows an attacker without script right to either create forms that can be used for phishing attacks or also in the context of a sheet, the attacker could add an input like `{{html}}<input type="hidden" name="content" value="{{groovy}}println("Hello from Groovy!")" />{{/html}}` that would allow remote code execution when it is submitted by an admin (the sheet is rendered as part of the edit form). The attacker would need to ensure that the edit form looks plausible, though, which can be non-trivial as without script right the attacker cannot display the regular content of the document. This has been patched in XWiki 14.10.6 and 15.2RC1 by removing the central form-related tags from the list of allowed tags. Users are advised to upgrade. As a workaround an admin can manually disallow the tags by adding `form, input, select, textarea, button` to the configuration option `xml.htmlElementSanitizer.forbidTags` in the `xwiki.properties` configuration file.
Vulnerability Analysis
CVE-2023-36471 can be exploited with network access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2023-36471. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is an Injection Vulnerability?
The software constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. Software has certain assumptions about what constitutes data and control respectively. It is the lack of verification of these assumptions for user-controlled input that leads to injection problems. Injection problems encompass a wide variety of issues -- all mitigated in very different ways and usually attempted in order to alter the control flow of the process. For this reason, the most effective way to discuss these weaknesses is to note the distinct features which classify them as injection weaknesses. The most important issue to note is that all injection problems share one thing in common -- i.e., they allow for the injection of control plane data into the user-controlled data plane. This means that the execution of the process may be altered by sending code in through legitimate data channels, using no other mechanism. While buffer overflows, and many other flaws, involve the use of some further issue to gain execution, injection problems need only for the data to be parsed. The most classic instantiations of this category of weakness are SQL injection and format string vulnerabilities.
CVE-2023-36471 has been classified to as an Injection vulnerability or weakness.
Products Associated with CVE-2023-36471
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Affected Versions
xwiki-commons:- Version >= 14.6-rc-1, < 14.10.6 is affected.
- Version >= 15.0-rc-1, < 15.2-rc-1 is affected.
Vulnerable Packages
The following package name and versions may be associated with CVE-2023-36471
| Package Manager | Vulnerable Package | Versions | Fixed In |
|---|---|---|---|
| maven | org.xwiki.commons:xwiki-commons-xml | >= 14.6-rc-1, < 14.10.6 | 14.10.6 |
| maven | org.xwiki.commons:xwiki-commons-xml | >= 15.0-rc-1, < 15.2-rc-1 | 15.2-rc-1 |
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.