Summary
ClassroomIO incorrectly authorizes lesson modification and deletion requests, allowing authenticated course members such as students to act beyond their intended permissions. By supplying lesson identifiers, an attacker may alter titles or stored HTML content and may delete lessons in their own or other courses and organizations.
ClassroomIO incorrectly authorizes lesson modification and deletion requests, allowing authenticated course members such as students to act beyond their intended permissions. By supplying lesson identifiers, an attacker may alter titles or stored HTML content and may delete lessons in their own or other courses and organizations.
Affected context
The vulnerability occurs in ClassroomIO deployments through version 1.0.0 where the PUT and DELETE /:lessonId lesson routes do not adequately verify whether the authenticated user is authorized to manage the referenced lesson. The risk is greatest when lesson identifiers can be supplied directly and authorization is based on course membership rather than an instructor, owner, or organization-level privilege check.
The vulnerability occurs in ClassroomIO deployments through version 1.0.0 where the PUT and DELETE /:lessonId lesson routes do not adequately verify whether the authenticated user is authorized to manage the referenced lesson. The risk is greatest when lesson identifiers can be supplied directly and authorization is based on course membership rather than an instructor, owner, or organization-level privilege check.
Exploit preconditions
- Attack surface: Authenticated HTTP PUT and DELETE lesson endpoints
- Required access: A valid account with course-member access, including a student account
- Trigger point: A request to a lesson route containing a chosen
lessonId - Why exploitation is possible: The server permits course members to perform management actions without sufficiently enforcing lesson ownership, instructor privileges, or organization boundaries
- Attack surface: Authenticated HTTP PUT and DELETE lesson endpoints
- Required access: A valid account with course-member access, including a student account
- Trigger point: A request to a lesson route containing a chosen
lessonId - Why exploitation is possible: The server permits course members to perform management actions without sufficiently enforcing lesson ownership, instructor privileges, or organization boundaries
Why this happens
The underlying issue is an authorization decision that does not correctly distinguish ordinary course membership from permission to modify or delete lessons. The route accepts a user-controlled lesson identifier but fails to enforce an appropriate object-level authorization policy for the referenced resource. This maps to CWE-863: Incorrect Authorization, where access-control checks are missing, incomplete, or applied to the wrong security principal or resource scope.
The underlying issue is an authorization decision that does not correctly distinguish ordinary course membership from permission to modify or delete lessons. The route accepts a user-controlled lesson identifier but fails to enforce an appropriate object-level authorization policy for the referenced resource. This maps to CWE-863: Incorrect Authorization, where access-control checks are missing, incomplete, or applied to the wrong security principal or resource scope.
Potential impact
- Students may modify lesson titles or stored HTML content
- Unauthorized users could delete lessons
- Course content integrity may be damaged
- Lessons in other courses or organizations could be affected
- Attackers may disrupt instruction or inject misleading content
- Administrative and tenant boundaries may be weakened
- Students may modify lesson titles or stored HTML content
- Unauthorized users could delete lessons
- Course content integrity may be damaged
- Lessons in other courses or organizations could be affected
- Attackers may disrupt instruction or inject misleading content
- Administrative and tenant boundaries may be weakened
General mitigation guidance
Mitigation generally focuses on enforcing object-level authorization at every lesson-management endpoint.
Common defensive patterns include:
- Requiring explicit instructor, owner, or administrator privileges for lesson updates and deletion
- Resolving the lesson from the authenticated user's permitted course and organization scope
- Denying access by default when ownership, role, or tenant membership cannot be established
- Avoiding authorization decisions based solely on client-supplied identifiers
- Applying consistent authorization checks to both read and write operations
- Using least-privilege roles and separating student capabilities from content-management capabilities
- Recording and reviewing authorization failures and destructive lesson operations
Mitigation generally focuses on enforcing object-level authorization at every lesson-management endpoint.
Common defensive patterns include:
- Requiring explicit instructor, owner, or administrator privileges for lesson updates and deletion
- Resolving the lesson from the authenticated user's permitted course and organization scope
- Denying access by default when ownership, role, or tenant membership cannot be established
- Avoiding authorization decisions based solely on client-supplied identifiers
- Applying consistent authorization checks to both read and write operations
- Using least-privilege roles and separating student capabilities from content-management capabilities
- Recording and reviewing authorization failures and destructive lesson operations
How teams detect issues like this
Organizations can identify similar issues through:
- Static analysis and code review checks for routes that use user-controlled object identifiers without nearby authorization enforcement
- Review of role and tenant checks on PUT, PATCH, and DELETE handlers
- Authorization matrix testing across students, instructors, administrators, courses, and organizations
- Negative tests confirming that users cannot modify or delete resources outside their permitted scope
- API gateway or policy enforcement that requires explicit resource-level permissions for destructive actions
- Audit-log analysis for unusual cross-course lesson changes or deletion attempts
Organizations can identify similar issues through:
- Static analysis and code review checks for routes that use user-controlled object identifiers without nearby authorization enforcement
- Review of role and tenant checks on PUT, PATCH, and DELETE handlers
- Authorization matrix testing across students, instructors, administrators, courses, and organizations
- Negative tests confirming that users cannot modify or delete resources outside their permitted scope
- API gateway or policy enforcement that requires explicit resource-level permissions for destructive actions
- Audit-log analysis for unusual cross-course lesson changes or deletion attempts
