Posted by Bug bounty hunters often encounter scenarios where email verification stands as a crucial barrier to unlocking important resources within a target. Gaining access to specific domains can open doors to a victim’s workspace, offering a glimpse into sensitive documents and content associated with whitelisted domains. In this blog post, we’ll delve into the intricacies of email verification bypass and explore effective strategies to showcase the real-time impact of these issues.
Identifying Features Dependent on Email Domain:
To effectively demonstrate the impact of email verification bypass, it’s essential to identify critical features linked to a user’s email domain. Some applications grant access to resources based on email domains, allowing users to join teams or workspaces directly if their email matches the team’s domain. Others restrict access to documents or videos through email domain whitelisting. Recognizing these features is the first step in showcasing the security impact of email verification bypass.
The Bypass Technique:
A powerful technique to bypass email verification involves a strategic sequence of steps:
- Log in to Attacker Account:
Start by logging into your attacker account and changing the email address to an attacker-controlled email (e.g., attackeremail@attackerdomain.com). - Receive Confirmation Link:
Expect to receive an email confirmation link on your attacker-controlled email. However, resist the temptation to verify it at this point. - Change to Target Email:
Change your email to the unregistered email or domain you wish to hijack (e.g., victimemail@victimdomain.com). This action triggers an email verification link sent to the victim’s email. - Exploiting Verification Link:
Attempt to click on the initial “Email” verification link sent to attackeremail@attackerdomain.com. If the system fails to revoke the previous email verification link, the link meant for the attacker-controlled email could inadvertently verify the victim’s email, allowing you to claim it as verified.
Proving Impact:
Once you have successfully claimed an email associated with another organization’s domain, it’s crucial to identify and showcase the associated functions to prove the impact. This might involve accessing restricted documents, viewing confidential content, or performing actions reserved for legitimate users within the organization.
Takeaways for Bug Bounty Hunters:
- Demonstrate Actual Impact:
Avoid reporting email verification issues without showcasing real-time impact. Security reports that highlight the practical consequences of a vulnerability are more likely to be recognized and rewarded. - Target Applications with Multiple Roles:
Applications supporting organizations or workspaces with multiple roles often rely on a person’s email domain. These applications are prime candidates for demonstrating the security impact of email verification bypass.
Conclusion:
Bug bounty hunting requires a combination of technical expertise and creative thinking. Unveiling the power of email verification bypass can be a game-changer in showcasing the real-world impact of security vulnerabilities. By strategically identifying features dependent on email domains and employing effective bypass techniques, bug bounty hunters can elevate their submissions and earn generous bounties while contributing to the overall improvement of digital security.
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