XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. In org.xwiki.platform:xwiki-platform-web versions 7.2-milestone-2 until 14.10.12 and org.xwiki.platform:xwiki-platform-web-templates prior to versions 14.10.12 and 15.5-rc-1, it is possible to pass a title to the page creation action that isnt displayed at first but then executed in the second step. This can be used by an attacker to trick a victim to execute code, allowing script execution if the victim has script right or remote code execution including full access to the XWiki instance if the victim has programming right.
For the attack to work, the attacker needs to convince the victim to visit a link like <xwiki-host>/xwiki/bin/create/NonExistingSpace/WebHome?title=$services.logging.getLogger(%22foo%22).error(%22Script%20executed!%22) where <xwiki-host> is the URL of the Wiki installation and to then click on the Create button on that page. The page looks like a regular XWiki page that the victim would also see when clicking the button to create a page that doesnt exist yet, the malicious code is not displayed anywhere on that page. After clicking the Create button, the malicious title would be displayed but at this point, the code has already been executed and the attacker could use this code also to hide the attack, e.g., by redirecting the victim again to the same page with an innocent title. It thus seems plausible that this attack could work if the attacker can place a fake create page button on a page which is possible with edit right.
This has been patched in org.xwiki.platform:xwiki-platform-web version 14.10.12 and org.xwiki.platform:xwiki-platform-web-templates versions 14.10.12 and 15.5-rc-1 by displaying the title already in the first step such that the victim can notice the attack before continuing. It is possible to manually patch the modified files from the patch in an existing installation. For the JavaScript change, the minified JavaScript file would need to be obtained from a build of XWiki and replaced accordingly.
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Xwiki | Xwiki | 7.3 (including) | 14.10.12 (excluding) |
| Xwiki | Xwiki | 15.0 (including) | 15.5 (excluding) |
| Xwiki | Xwiki | 7.2-milestone2 (including) | 7.2-milestone2 (including) |
| Xwiki | Xwiki | 7.2-milestone3 (including) | 7.2-milestone3 (including) |
Improper encoding or escaping can allow attackers to change the commands that are sent to another component, inserting malicious commands instead. Most products follow a certain protocol that uses structured messages for communication between components, such as queries or commands. These structured messages can contain raw data interspersed with metadata or control information. For example, “GET /index.html HTTP/1.1” is a structured message containing a command (“GET”) with a single argument ("/index.html") and metadata about which protocol version is being used (“HTTP/1.1”). If an application uses attacker-supplied inputs to construct a structured message without properly encoding or escaping, then the attacker could insert special characters that will cause the data to be interpreted as control information or metadata. Consequently, the component that receives the output will perform the wrong operations, or otherwise interpret the data incorrectly.