Summary
Apache Roller contains an authorization flaw in its OAuth 1.0a authorization endpoint that can let an unauthenticated remote attacker associate a valid request token with an arbitrary user account. The issue becomes critical when a site-wide OAuth consumer is configured and the attacker has learned one of its outstanding request tokens.
Affected context
The vulnerability affects Apache Roller installations that configure an OAuth 1.0a site-wide consumer. It occurs in the authorization endpoint when the authorizing identity is taken from a request-supplied value instead of being securely tied to the authenticated user session. Exploitation also depends on an attacker obtaining an outstanding request token.
Exploit preconditions
- Attack surface: Internet-accessible OAuth 1.0a authorization endpoint
- Required access: No authenticated account is required, but the attacker must know an outstanding request token belonging to a configured site-wide consumer
- Trigger point: Submission of an authorization request to the OAuth endpoint
- Request condition: The request can be submitted without a valid signature and can supply an account identity
- Why exploitation is possible: The endpoint trusts the request-supplied identity rather than binding authorization to the currently authenticated session
Why this happens
The underlying bug is an authorization context-confusion error. The OAuth authorization endpoint uses identity data supplied by the request to determine which account is authorizing a request, rather than deriving that identity exclusively from the authenticated session. This maps to CWE-863: Incorrect Authorization, because the application can authorize an operation for an account that the requester has not legitimately authenticated as.
Potential impact
- An attacker may bind an OAuth request token to an arbitrary user account
- An attacker could obtain OAuth authorization associated with an administrator account
- Unauthorized access to protected Roller capabilities may result
- Account takeover or privilege escalation could occur
- Connected applications may receive access beyond the attacker's intended privileges
General mitigation guidance
Mitigation generally focuses on making the authenticated session the sole source of authorization identity.
Common defensive patterns include:
- Bind OAuth authorization decisions to the server-side authenticated session
- Ignore or reject request parameters that attempt to select the authorizing account
- Require complete request validation and integrity protection before authorization
- Limit site-wide consumer privileges and apply least-privilege scopes
- Protect request tokens from disclosure, reuse, and cross-user association
- Expire outstanding request tokens promptly and invalidate them after use
- Apply consistent authorization checks to administrator and non-administrator accounts
How teams detect issues like this
Organizations can identify similar authorization flaws through:
- Static analysis for authorization decisions based on request parameters rather than session context
- Code review checks for OAuth endpoints that accept user identity, account, or principal identifiers from clients
- Tests that attempt to authorize one account while authenticated as another account
- Negative tests for unsigned, replayed, expired, or cross-user request tokens
- Policy enforcement requiring server-side identity binding for authorization workflows
- Logging and alerting on unusual token-to-account associations or administrative authorizations
- Automated security review tools that flag missing authorization checks and identity confusion patterns
