Full Report
Ticket Tricking is a technique to get OTPs or verification emails sent to a public forum so that you can "prove" you have access to a domain when you really don't. Google Groups have this risk and are the focus of this post. The author of the post found a tool for scraping Google Groups. Unfortunately, it was somewhat outdated and only looked for a single hard-coded group. So, they wrote a Vibe-Coded application to find Google Group URLs, filter them, and check for public read access. After scanning from 32K raw URLs, they were left with 150+ groups. One of the vulnerable instances was OpenSSL.org Slack group. The author logged in to the group using the OTP leaked on the forum. The end result is that there are serious implications to this. Many applications (except Slack) have patched vulnerable-by-default mechanisms. However, GitHub email verification, auto-join SaaS tenants and many other things are still vulnerable. Good post!
Analysis Summary
# Vulnerability: Ticket Tricking via Public Google Groups
## CVE Details
- **CVE ID**: N/A (Business Logic Flaw / Misconfiguration)
- **CVSS Score**: N/A - Severity varies based on the target system (typically considered **High** due to identity theft implications)
- **CWE**: CWE-284: Improper Access Control; CWE-1391: Use of Weak Credentials (via predictable/accessible OTPs)
## Affected Systems
- **Products**: Google Groups, and any SaaS/Service relying on email-based verification (e.g., Slack, GitHub, internal corporate portals).
- **Versions**: Cloud-based/SaaS (current).
- **Configurations**:
- Google Groups set to "Public" visibility with "Anyone can view" and "Anyone can post" enabled.
- Application tenants configured to allow "Auto-join" for specific domain suffixes (e.g., `@company.com`).
- Services using Email OTP or "Magic Links" for authentication without additional factors.
## Vulnerability Description
"Ticket Tricking" is an exploitation technique where an attacker triggers a verification email or One-Time Password (OTP) from a target service (like Slack or GitHub) to an email address associated with a public forum or helpdesk.
When a Google Group is misconfigured to allow public read access, the verification email—sent to the group's email address—is archived and indexed publicly. The attacker monitors the group, retrieves the OTP or verification link, and uses it to assume the identity of a domain user. This allows the attacker to register accounts, join private workspaces, or sign commits as a legitimate member of the target organization.
## Exploitation
- **Status**: PoC available / Actively exploitable (confirmed against OpenSSL.org's community portal and others).
- **Complexity**: Low.
- **Attack Vector**: Network.
## Impact
- **Confidentiality**: High (Access to internal communications, SaaS tenants, and private project data).
- **Integrity**: High (Ability to verify GitHub commits or modify settings as an official domain user).
- **Availability**: Low (Primary impact is unauthorized access rather than service disruption).
## Remediation
### Patches
- This is a configuration and architectural issue rather than a software bug; therefore, no single software patch exists. Organizations must audit their specific Google Workspace settings.
### Workarounds
- **Identity Standards**: Transition from email-based authentication (OTP/Magic Links) to robust standards like OIDC or SAML.
- **Admin Policies**: Disable the ability for Google Groups to have external members or be public unless strictly necessary.
- **SaaS Configuration**: Disable "Auto-join" features in Slack or other SaaS tools that allow anyone with a specific domain email to join automatically.
## Detection
- **Indicators of Compromise**:
- Unexpected account registrations from administrative or group email addresses (e.g., `info@`, `support@`, `dev@`).
- New members joining SaaS tenants from unconventional IP addresses using domain-validated accounts.
- **Detection Methods and Tools**:
- **vibe-sec-tools**: A Golang-based toolset for scanning and filtering public Google Groups for read/write access.
- **Manual Audit**: Admins should review the "Access settings" for all Google Groups within the organization's Workspace.
## References
- **Original Post**: hxxps://spaceraccoon[.]dev/ticket-trick-openssl-google-groups/
- **Original Technique**: hxxps://medium[.]com/intigriti/how-i-hacked-hundreds-of-companies-through-their-helpdesk-b7680ddc2d4c
- **Google Workspace Admin Help**: hxxps://support[.]google[.]com/a/answer/167097?hl=en