CVE-2022-36100

XWiki Platform Applications Tag and XWiki Platform Tag UI are tag applications for XWiki, a generic wiki platform. Starting with version 1.7 in XWiki Platform Applications Tag and prior to 13.10.6 and 14.4 in XWiki Platform Tag UI, the tags document Main.Tags in XWiki didnt sanitize user inputs properly. This allowed users with view rights on the document (default in a public wiki or for authenticated users on private wikis) to execute arbitrary Groovy, Python and Velocity code with programming rights. This also allowed bypassing all rights checks and thus both modification and disclosure of all content stored in the XWiki installation. The vulnerability could be used to impact the availability of the wiki. On XWiki versions before 13.10.4 and 14.2, this can be combined with CVE-2022-36092, meaning that no rights are required to perform the attack. The vulnerability has been patched in versions 13.10.6 and 14.4. As a workaround, the patch that fixes the issue can be manually applied to the document Main.Tags or the updated version of that document can be imported from version 14.4 of xwiki-platform-tag-ui using the import feature in the administration UI on XWiki 10.9 and later.

Weakness

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.

Affected Software

Extended Description

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.

Potential Mitigations

• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, consider using the ESAPI Encoding control [REF-45] or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error.
• Alternately, use built-in functions, but consider using wrappers in case those functions are discovered to have a vulnerability.
• If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.
• For example, stored procedures can enforce database query structure and reduce the likelihood of SQL injection.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/104.html
• https://cwe.mitre.org/data/definitions/73.html
• https://cwe.mitre.org/data/definitions/81.html
• https://cwe.mitre.org/data/definitions/85.html

References

• https://github.com/xwiki/xwiki-platform/commit/604868033ebd191cf2d1e94db336f0c4d9096427
• https://github.com/xwiki/xwiki-platform/security/advisories/GHSA-2g5c-228j-p52x
• https://jira.xwiki.org/browse/XWIKI-19747