CVE-2023-30537

XWiki Platform allows code execution via unescaped styles in FlamingoThemesCode.WebHome

• CVSS 8.8
• CWE-94 Improper Control of Generation of Code ('Code Injection')
• Input Validation and Sanitization
• Remote

XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Any user with the right to add an object on a page can execute arbitrary Groovy, Python or Velocity code in XWiki leading to full access to the XWiki installation. The root cause is improper escaping of the styles properties `FlamingoThemesCode.WebHome`. This page is installed by default. The vulnerability has been patched in XWiki versions 13.10.11, 14.4.7 and 14.10.

CVE

CVE-2023-30537

CWE

CWE-94 Improper Control of Generation of Code ('Code Injection')

CVSS base score

8.8

Published

2023-04-16

OWASP

A03 Injection

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Input Validation and Sanitization

Subcategory

Command Injection

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Fixed by upgrading

Yes

Solution

Update to XWiki versions 13.10.11, 14.4.7, or 14.10.

def execute_user_input(style_properties):
    """Vulnerable function that demonstrates the security issue."""
    user_input = f"style={{ {style_properties} }}"
    eval(user_input)

import ast

def escape_style_properties(style_properties):
    """Secure function that fixes the vulnerability."""
    escaped_properties = {}
    for key, value in style_properties.items():
        modified_key = key.replace(";", "").replace("}", "").replace("{", "")
        modified_value = value.replace(";", "").replace("}", "").replace("{", "")
        escaped_properties[modified_key] = modified_value
    return escaped_properties

def execute_user_input(style_properties):
    """Secure function that fixes the vulnerability."""
    escaped = escape_style_properties(style_properties)
    style_string = f"{{ {', '.join([f'{key}: {value}' for key, value in escaped.items()])} }}"
    
    try:
        ast.literal_eval(style_string)
    except (ValueError, SyntaxError) as e:
        print(f"Error evaluating the style string: {e}")
        return None

@misc{vaitp:cve202330537,
  title        = {{XWiki Platform allows code execution via unescaped styles in FlamingoThemesCode.WebHome}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2023},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2023-30537},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2023-30537/}}
}