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How CVE-2020-15245 Works
This vulnerability resides in the email update functionality of Sylius, an open-source e-commerce platform. The core issue is a failure to invalidate the existing email verification state when a user changes their email address. In a properly designed system, changing a primary account email should trigger a re-verification process for the new address, resetting the `verified` status to `false` until the new email is confirmed.
However, in vulnerable versions of Sylius, the system does not reset the verification flag. The `verification` column in the database remains set to `true` even after the email is changed to an arbitrary, unverified, or unowned address.
An attacker can exploit this by first registering an account with a legitimate email address they control and completing the verification process. Once the account is verified, the attacker uses the profile settings to change the account’s email to any other address—such as one belonging to a victim or a non-existent mailbox. The system saves this new email without any validation or confirmation challenge.
Because the `verified` status is never reset, the account retains its verified badge and all associated privileges. The platform continues to treat the account as fully verified, even though it is now linked to an email address the user does not actually own or control.
This bypasses the fundamental trust assumption that a verified email indicates ownership. It allows malicious actors to misrepresent their identity, associate their account with another person’s email, and potentially abuse features that are gated behind verified status—such as elevated permissions, access to restricted areas, or trust-based workflows.
The vulnerability was patched in Sylius versions 1.6.9, 1.7.9, and 1.8.3.
DailyCVE Form
Platform: Sylius
Version: < 1.6.9, < 1.7.9, < 1.8.3
Vulnerability: Email verification bypass
Severity: Moderate
Date: 2020-10-19
Prediction: 2020-10-19 (Patched)
What Undercode Say
Analytics: This vulnerability is a classic case of state management failure during a critical user profile update. The security flaw lies in the fact that the `verified` flag is treated as a persistent attribute of the user account rather than a property of the current email address.
“When a user changes their email, the verification status should be atomically tied to the new email. Failing to reset this flag creates a logical inconsistency that can be exploited for identity fraud.”
Code Behavior: The issue occurs because the email update handler does not include a verification reset routine. A typical vulnerable code flow might look like:// VULNERABLE: Email update without resetting verification public function updateEmail(User $user, string $newEmail): void { $user->setEmail($newEmail); // Verification status remains unchanged (still true) $this->entityManager->flush(); }Patched Version: The fix involves resetting the verification status whenever the email is changed:
// PATCHED: Reset verification on email change public function updateEmail(User $user, string $newEmail): void { $user->setEmail($newEmail); $user->setVerified(false); // Force re-verification $this->entityManager->flush(); }
How Exploit
An attacker can exploit this vulnerability with the following steps:
1. Register a new account using a legitimate, controllable email address (e.g., [email protected]).
2. Verify the email address through the standard verification process (clicking the confirmation link).
3. Navigate to the profile settings and change the account email to a target address (e.g., [email protected]).
4. Save the changes. The system updates the email but does not invalidate the `verified` status.
5. The account now appears as verified while being associated with an email the attacker does not own.
Impact of Exploitation:
- The attacker can claim ownership of an email address they do not control.
- The platform may send sensitive notifications or password reset links to the victim’s email, potentially leading to information disclosure.
- The attacker can bypass verification-based trust assumptions and access features restricted to verified users.
- This does not allow direct takeover of existing accounts.
Protection
- Upgrade to Sylius version 1.6.9, 1.7.9, 1.8.3, or later.
- If upgrading is not immediately possible, implement a custom event listener for the `sylius.customer.pre_update` event to detect email changes and reset the verification status.
- Validate that the email change is accompanied by a new verification flow before marking the account as verified.
- Monitor user activity for suspicious email change patterns, especially rapid changes followed by verification status anomalies.
Impact
- Misrepresentation of email ownership: An attacker can link a verified account to an arbitrary email address.
- Bypass of trust assumptions: Features that rely on verified email status can be abused.
- Information disclosure: Notifications or sensitive communications sent to the unowned email may be exposed.
- No direct account takeover: This vulnerability alone does not grant access to other users’ accounts.
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Sources:
Reported By: github.com
Extra Source Hub:
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