CVE-2023-48171

Executive Summary

CVE-2023-48171 is a privilege escalation vulnerability in OWASP DefectDojo, an open-source application vulnerability management tool. The flaw exists in versions prior to 1.5.3.1 and allows a remote attacker to escalate their privileges via the user permissions component. This vulnerability is particularly dangerous as it can allow an authenticated low-privileged user to gain administrative access, potentially leading to full compromise of the DefectDojo instance and exposure of sensitive vulnerability data.

Supply Chain & Package Security

DefectDojo is a Python/Django application distributed via PyPI and Docker. Organizations using DefectDojo should verify they are not running a vulnerable version in their software supply chain. The package is defectdojo on PyPI. Ensure that any CI/CD pipelines or container registries are updated to version 1.5.3.1 or later.

CVSS Breakdown & Threat Level

CVSS Score: 0.0 (No official CVSS vector assigned by NVD) EPSS Score: 0.0% (Low probability of exploitation in the wild) Threat Level: Medium (Based on the nature of privilege escalation in a security tool)

While no official CVSS vector is available, based on the vulnerability description, a reasonable assessment would be:

• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (authenticated user)
• User Interaction: None
• Scope: Changed
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

This would result in a CVSS v3.1 score of approximately 8.8 (High).

Deep Dive & Mechanics

The vulnerability resides in the user permissions component of DefectDojo. The application uses a role-based access control (RBAC) system to manage user permissions. The flaw allows an authenticated user to manipulate their own permissions or the permissions of other users, effectively escalating their privileges to that of an administrator.

The exact mechanism is not publicly documented, but based on the nature of similar vulnerabilities in Django applications, it likely involves:

1. Insecure Direct Object Reference (IDOR): The application may not properly validate that a user is authorized to modify their own or another user's permission settings.
2. Missing Server-Side Validation: The client-side permission controls may not be enforced on the server, allowing a user to send crafted HTTP requests to modify their role.
3. Mass Assignment Vulnerability: The Django REST framework or forms may allow mass assignment of user attributes, including the is_superuser or groups fields.

An attacker would need to be an authenticated user with at least basic access to the DefectDojo instance. They could then craft a request to modify their user profile or group membership to gain administrative privileges.

Vulnerable vs. Patched Code

The patch for this vulnerability is included in version 1.5.3.1. The fix likely involves:

• Adding proper permission checks in the user profile and group management views.
• Implementing server-side validation to ensure users can only modify their own non-privileged attributes.
• Preventing mass assignment of sensitive fields like is_superuser or groups.

Vulnerable Code (Conceptual):

# views.py (vulnerable)
class UserProfileUpdateView(UpdateView):
    model = User
    fields = ['username', 'email', 'is_superuser', 'groups']  # Mass assignment vulnerability
    def get_object(self):
        return self.request.user  # No permission check

Patched Code (Conceptual):

# views.py (patched)
class UserProfileUpdateView(UpdateView):
    model = User
    fields = ['username', 'email']  # Removed sensitive fields
    def get_object(self):
        user = self.request.user
        if not user.is_superuser:
            raise PermissionDenied
        return user

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Access to a DefectDojo instance running version < 1.5.3.1
• Valid user credentials with low privileges (e.g., a "Reader" or "Developer" role)

Exploitation Steps:

1. Authenticate to DefectDojo and obtain a session cookie or API token.

2. Identify the user profile endpoint. This is typically /api/v2/users/{id}/ or /profile/.

3. Craft a privilege escalation request. Using a tool like curl or Burp Suite, send a PUT/PATCH request to modify the user's role.

# Example using curl to escalate privileges via API
curl -X PATCH \
  -H "Authorization: Token <your_token>" \
  -H "Content-Type: application/json" \
  -d '{"is_superuser": true, "groups": [1]}' \
  http://target/api/v2/users/1/

4. Verify escalation. Access an admin-only endpoint, such as /api/v2/users/ to list all users.

Note: The exact endpoint and payload may vary. This is a conceptual example based on common Django REST framework patterns.

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual API requests to user management endpoints (e.g., /api/v2/users/).
• Alert on changes to user roles or group memberships, especially if performed by non-admin users.
• Look for HTTP 403 errors followed by successful modifications to user profiles.

Hardening:

• Immediately upgrade to DefectDojo version 1.5.3.1 or later.
• Implement network segmentation to restrict access to the DefectDojo instance.
• Enable audit logging and monitor for privilege escalation attempts.
• Use a Web Application Firewall (WAF) to block suspicious API requests.

Indicators of Compromise (IOCs)

Network IOCs:

• Unusual PATCH/PUT requests to /api/v2/users/ endpoints from non-admin IP addresses.
• HTTP requests containing "is_superuser": true or "groups": [1] in the request body.

System IOCs:

• New user accounts with administrative privileges created outside of normal processes.
• Changes to user group memberships in the DefectDojo database.
• Audit log entries showing privilege escalation events.

File IOCs:

• Modified user profile data in the DefectDojo database (SQLite or PostgreSQL).
• Unusual entries in the Django admin log.

Detection Engineering

YARA Rule

rule Detect_DefectDojo_PrivEsc_CVE_2023_48171 {
    meta:
        description = "Detects potential privilege escalation attempts against DefectDojo CVE-2023-48171"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2023-48171"
    strings:
        $s1 = "is_superuser" ascii wide nocase
        $s2 = "groups" ascii wide nocase
        $s3 = "/api/v2/users/" ascii wide nocase
        $s4 = "PATCH" ascii wide nocase
        $s5 = "PUT" ascii wide nocase
    condition:
        all of ($s1, $s2, $s3) and any of ($s4, $s5)
}

Sigma Rule

title: DefectDojo Privilege Escalation Attempt (CVE-2023-48171)
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests attempting to exploit CVE-2023-48171 in DefectDojo
author: Valters IT
date: 2024-01-01
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 
            - 'PATCH'
            - 'PUT'
        cs-uri-query|contains: '/api/v2/users/'
        cs-uri-query|contains: 
            - 'is_superuser'
            - 'groups'
    condition: selection
falsepositives:
    - Legitimate administrative actions
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-48171 DefectDojo Privilege Escalation Attempt"; flow:to_server; content:"PATCH"; http_method; content:"/api/v2/users/"; http_uri; content:"is_superuser"; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade DefectDojo to version 1.5.3.1 or later. This is the only complete fix.
2. If immediate upgrade is not possible, restrict access to the DefectDojo instance to trusted IP addresses only.
3. Review all user accounts and permissions for any signs of unauthorized escalation.

Long-Term Mitigations:

• Implement the principle of least privilege for all DefectDojo users.
• Enable comprehensive audit logging and monitor for suspicious activity.
• Regularly update DefectDojo and its dependencies.
• Use a Web Application Firewall (WAF) with rules to block privilege escalation attempts.
• Conduct regular security assessments of the DefectDojo deployment.

Workarounds (if patching is delayed):

• Disable user self-registration if enabled.
• Manually review and restrict API access to user management endpoints.
• Implement additional authentication factors for administrative actions.

Valters IT