CVE-2023-6152: Grafana Email Verification Bypass Flaw

CVE-2023-6152 Overview

CVE-2023-6152 is an authorization bypass vulnerability affecting Grafana, the popular open-source analytics and monitoring platform. The vulnerability allows authenticated users to change their email address in profile settings without proper verification, even after their initial email was verified during sign-up. This occurs because the verify_email_enabled configuration option only validates email addresses during the registration process, not during subsequent email changes.

Critical Impact

Authenticated users can bypass email verification controls, potentially leading to account integrity issues, unauthorized access to email-gated features, and impersonation attacks within Grafana environments.

Affected Products

• Grafana versions prior to patched releases
• Grafana 10.0.0
• Grafana 10.1.0
• Grafana 10.2.0
• Grafana 10.3.0

Discovery Timeline

• 2024-02-13 - CVE-2023-6152 published to NVD
• 2025-02-15 - Last updated in NVD database

Technical Details for CVE-2023-6152

Vulnerability Analysis

This vulnerability stems from an improper authorization check (CWE-863) in Grafana's email verification workflow. The platform's email verification mechanism is designed to ensure users have access to the email addresses they register with. However, the verification logic is inconsistently applied—it enforces verification during the initial sign-up process but fails to re-verify email addresses when users modify them through their profile settings.

An authenticated attacker could exploit this flaw to change their registered email to any arbitrary address without proving ownership. This bypass undermines the integrity guarantees that email verification is meant to provide, such as ensuring communications reach legitimate account holders and preventing users from associating accounts with emails they don't control.

Root Cause

The root cause is an incomplete implementation of the email verification feature. The verify_email_enabled configuration setting is only checked and enforced during the user registration flow. The profile settings update endpoint lacks the corresponding verification check, creating an authorization gap where email changes bypass the intended security control entirely.

Attack Vector

The attack is network-based and requires low privileges (an authenticated user account). An attacker with valid credentials can access the profile settings functionality and submit a request to change their email address. Since the backend does not enforce verification for email updates, the change is accepted immediately. This could enable attackers to:

1. Bypass email-based access controls or notifications
2. Receive password reset emails intended for other users (if combined with other attack vectors)
3. Impersonate other users by claiming their email addresses
4. Undermine audit trails that rely on verified email addresses

The vulnerability requires no user interaction beyond the attacker's own actions, making it straightforward to exploit once authentication is achieved.

Detection Methods for CVE-2023-6152

Indicators of Compromise

• User accounts with email addresses that changed without corresponding verification records
• Multiple email address changes for a single account in short time periods
• Profile update API calls that modify email addresses without subsequent verification token requests
• Users with email domains inconsistent with organizational policies

Detection Strategies

• Monitor Grafana audit logs for profile update events that include email address modifications
• Implement alerting for users changing email addresses without completing email verification workflows
• Review user profile modification patterns for anomalous behavior such as rapid email changes
• Cross-reference email change events against verification completion events to identify bypasses

Monitoring Recommendations

• Enable comprehensive audit logging for all user profile modifications in Grafana
• Set up alerts for email address changes, particularly to external or unexpected domains
• Periodically audit user accounts to verify email addresses are legitimately owned
• Monitor authentication patterns following email address changes for signs of account takeover

How to Mitigate CVE-2023-6152

Immediate Actions Required

• Upgrade Grafana to the latest patched version immediately
• Review audit logs to identify any accounts that may have exploited this vulnerability
• Consider manually verifying email addresses for critical accounts
• Implement additional access controls or approval workflows for email changes if possible

Patch Information

Grafana has released security patches to address this vulnerability. Administrators should upgrade to the latest available version of Grafana that includes the fix. Detailed patch information and affected version ranges are available in the Grafana Security Advisory and the GitHub Security Advisory.

Workarounds

• Disable user self-service email changes by restricting profile modification permissions
• Implement organizational policies requiring administrator approval for email address changes
• Use external identity providers (LDAP, OAuth, SAML) that manage email addresses outside of Grafana
• Monitor and alert on all email address changes until patching is complete

# Configuration example - Review and update Grafana configuration
# Ensure verify_email_enabled is set and consider additional restrictions
[users]
verify_email_enabled = true
# Consider restricting profile editing if self-service email changes are not required
allow_sign_up = false