CVE-2023-48240
CVE-2023-48240
CVSS Vector
v3.1- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- Low
- User Interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Description
XWiki Platform is a generic wiki platform. The rendered diff in XWiki embeds images to be able to compare the contents and not display a difference for an actually unchanged image. For this, XWiki requests all embedded images on the server side. These requests are also sent for images from other domains and include all cookies that were sent in the original request to ensure that images with restricted view right can be compared. Starting in version 11.10.1 and prior to versions 14.10.15, 15.5.1, and 15.6, this allows an attacker to steal login and session cookies that allow impersonating the current user who views the diff. The attack can be triggered with an image that references the rendered diff, thus making it easy to trigger. Apart from stealing login cookies, this also allows server-side request forgery (the result of any successful request is returned in the image's source) and viewing protected content as once a resource is cached, it is returned for all users. As only successful requests are cached, the cache will be filled by the first user who is allowed to access the resource. This has been patched in XWiki 14.10.15, 15.5.1 and 15.6. The rendered diff now only downloads images from trusted domains. Further, cookies are only sent when the image's domain is the same the requested domain. The cache has been changed to be specific for each user. As a workaround, the image embedding feature can be disabled by deleting `xwiki-platform-diff-xml-<version>.jar` in `WEB-INF/lib/`.
Comprehensive Technical Analysis of CVE-2023-48240
1. Vulnerability Assessment and Severity Evaluation
CVE ID: CVE-2023-48240 CVSS Score: 9
Severity Evaluation: The CVSS score of 9 indicates a critical vulnerability. This high score is justified by the potential for unauthorized access to sensitive information, impersonation of users, and server-side request forgery (SSRF). The vulnerability allows an attacker to steal login and session cookies, which can lead to severe security breaches, including unauthorized access to user accounts and sensitive data.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Cookie Theft: An attacker can exploit the vulnerability by embedding an image in the rendered diff that references a URL designed to capture cookies. When a user views the diff, the server-side request includes all cookies, which can be intercepted by the attacker.
- Server-Side Request Forgery (SSRF): The vulnerability allows an attacker to make arbitrary requests to internal or external services, potentially accessing sensitive data or performing actions on behalf of the user.
- Unauthorized Access to Protected Content: Once a resource is cached, it can be accessed by any user, leading to unauthorized access to protected content.
Exploitation Methods:
- Image Embedding: An attacker can embed a malicious image in the rendered diff, which triggers the server-side request with the user's cookies.
- Caching Exploitation: By exploiting the caching mechanism, an attacker can access protected content that has been cached by a user with appropriate permissions.
3. Affected Systems and Software Versions
Affected Versions:
- XWiki Platform versions starting from 11.10.1 up to but not including 14.10.15, 15.5.1, and 15.6.
Unaffected Versions:
- XWiki Platform versions 14.10.15, 15.5.1, and 15.6 and later.
4. Recommended Mitigation Strategies
Immediate Mitigation:
- Disable Image Embedding: As a temporary workaround, disable the image embedding feature by deleting
xwiki-platform-diff-xml-<version>.jarinWEB-INF/lib/.
Long-Term Mitigation:
- Upgrade to Patched Versions: Upgrade to XWiki Platform versions 14.10.15, 15.5.1, or 15.6, which include the necessary patches.
- Restrict Image Domains: Ensure that images are only downloaded from trusted domains and that cookies are only sent when the image's domain matches the requested domain.
- User-Specific Caching: Implement user-specific caching to prevent unauthorized access to cached content.
5. Impact on Cybersecurity Landscape
Broader Implications:
- Increased Awareness: This vulnerability highlights the importance of securing server-side requests and managing cookies carefully.
- Best Practices: It reinforces the need for robust security practices, including regular updates, careful handling of cookies, and secure caching mechanisms.
- Potential for Widespread Impact: Given the widespread use of wiki platforms, this vulnerability underscores the potential for significant impact if exploited, affecting numerous organizations and users.
6. Technical Details for Security Professionals
Technical Overview:
- Vulnerability Mechanism: The vulnerability arises from the way XWiki handles image requests in the rendered diff. The server-side requests include all cookies, which can be exploited to steal login and session cookies.
- Patch Details: The patch ensures that images are only downloaded from trusted domains and that cookies are only sent when the image's domain matches the requested domain. Additionally, the caching mechanism has been modified to be user-specific.
- Workaround Implementation: To disable the image embedding feature, remove the
xwiki-platform-diff-xml-<version>.jarfile from theWEB-INF/lib/directory.
References:
Conclusion: CVE-2023-48240 is a critical vulnerability that underscores the importance of secure handling of server-side requests and cookies. Organizations using XWiki Platform should prioritize upgrading to patched versions and implementing the recommended mitigation strategies to protect against potential exploitation.