Summary
Froxlor through version 2.3.10 can incorrectly accept a remembered two-factor authentication token across customer and administrator account namespaces when both accounts share the same numeric ID. An attacker who controls the colliding customer account and knows the administrator's password may bypass the administrator's TOTP challenge and obtain an authenticated administrator session.
Affected context
The issue occurs in Froxlor installations that use remembered-2FA tokens and maintain separate customer and administrator ID namespaces. The panel_2fa_tokens data and login lookup identify accounts by numeric user ID without preserving or enforcing the account type, allowing an otherwise valid customer token to be considered for an administrator with the same ID.
Exploit preconditions
- Attack surface: The remembered-2FA token authentication flow
- Required access: Control of a customer account whose numeric ID collides with a target administrator ID, possession of that customer's valid remembered-2FA cookie, and knowledge of the target administrator's password
- Trigger point: Administrator login when Froxlor validates the remembered-2FA token
- Why exploitation is possible: Token lookup is not constrained by account namespace, so a customer token can satisfy the second-factor check for a matching administrator ID
Why this happens
The underlying flaw is an authentication identity-binding failure. Froxlor stores and resolves remembered-2FA tokens using only a numeric identifier, even though customer and administrator accounts use separate identifier namespaces. Because the account type is omitted from the token identity and lookup constraint, a token valid for one principal can be associated with another principal sharing the same ID. This maps to CWE-287: Improper Authentication.
Potential impact
- An attacker may bypass the administrator's remembered-2FA or TOTP requirement
- An attacker could obtain an authenticated administrator session
- Administrative settings and managed data may be accessed or modified
- The incident could enable account, hosting, or configuration changes within the affected Froxlor installation
General mitigation guidance
Mitigation generally focuses on binding every authentication artifact to the complete account identity rather than to a numeric ID alone.
Common defensive patterns include:
- Including an explicit account namespace or principal type in token records and lookup conditions
- Invalidating remembered-2FA tokens when account identity attributes change
- Requiring fresh, correctly scoped second-factor verification for privileged sessions
- Applying least privilege to administrative accounts and session capabilities
- Treating remembered authentication cookies as scoped credentials and protecting them with secure cookie attributes
- Reviewing existing remembered tokens after identity-binding logic is corrected
How teams detect issues like this
Organizations can assess for this class of issue through:
- Static analysis that checks whether authentication-token queries constrain all principal identity dimensions
- Code review of remembered-login, session restoration, and MFA bypass paths
- Tests that create customer and administrator accounts with identical numeric IDs and verify strict namespace separation
- Log analysis for administrator sessions established through tokens issued to a different account type
- Policy checks requiring privileged authentication artifacts to include an immutable, unambiguous principal identifier
Automated security testing and code-review tools may help identify missing account-type constraints.
