Executive Summary

A database containing the personal details of 29.8 million SoundCloud users has been leaked publicly following a data breach. The incident, which was indexed by the breach notification service HaveIBeenPwned on January 27, 2026, reportedly occurred after threat actors attempted to extort the company and were refused payment. The compromised database links users' private email addresses to their public profile information. While passwords were not included, this combination of data creates a significant risk for the affected users, who are now exposed to highly targeted phishing attacks, credential stuffing, and other forms of social engineering.

Threat Overview

• Victim: SoundCloud
• Impact: 29.8 million user records exposed.
• Exposed Data: Private email addresses linked to public profile metadata (e.g., usernames, profile names, location if public).
• Attack Timeline: The data was released publicly in January 2026 after a failed ransom attempt.

The core threat from this breach is the loss of anonymity and the correlation of private contact information (email) with public personas. For many users, particularly artists and creators, their SoundCloud profile is a public brand, but the associated email address was intended to be private. Attackers can now directly link these two pieces of information.

Technical Analysis

The exact method of the breach has not been disclosed by SoundCloud. However, breaches of this type typically result from one of several common scenarios:

• Leaky API Endpoint: A misconfigured or unprotected API endpoint could have allowed the attacker to enumerate user profiles and their associated email addresses.
• Database Compromise: The attacker may have gained access to a backup or production database through a vulnerability, misconfiguration, or compromised credentials.
• Third-Party Breach: A third-party vendor with access to SoundCloud's user data could have been the source of the compromise.

Potential MITRE ATT&CK TTPs

• Initial Access: T1190 - Exploit Public-Facing Application, T1078 - Valid Accounts
• Collection: T1530 - Data from Cloud Storage Object, T1074 - Data Staged
• Exfiltration: T1048.003 - Exfiltration Over Alternative Protocol: Exfiltration Over Unencrypted/Obfuscated Non-C2 Protocol

Impact Assessment

For the 29.8 million affected users, the risks are significant and long-lasting:

• Targeted Phishing: Attackers can craft highly convincing phishing emails that reference the user's SoundCloud username or profile, making the emails seem legitimate. These emails can be used to steal passwords for SoundCloud or other services.
• Credential Stuffing: While passwords were not in this leak, attackers will take the list of 29.8 million email addresses and try to use them with commonly used passwords (or passwords from other breaches) to break into SoundCloud accounts and other online services where the user has reused their password. This is a form of D3FEND Credential Stuffing.
• Spam and Harassment: Users are likely to see an increase in spam directed at their leaked email addresses. They may also be targeted for harassment.
• Reputational Damage to SoundCloud: The breach damages SoundCloud's reputation and erodes user trust in the platform's ability to protect their private information.

Detection & Response (for Affected Users)

Users can check if they were part of this breach by visiting a reputable breach notification service like HaveIBeenPwned.

• Password Reset: Immediately change your SoundCloud password. Even though passwords were not leaked, it is a critical precautionary step.
• Enable Multi-Factor Authentication (MFA): Enable MFA on your SoundCloud account. This is the most effective way to prevent your account from being taken over via credential stuffing. This is a core tenant of D3FEND Multi-factor Authentication.
• Beware of Phishing: Be extremely vigilant for any emails that claim to be from SoundCloud regarding the breach. Do not click on links or download attachments. Go directly to the SoundCloud website for official information.
• Unique Passwords: Use a password manager to ensure you are using a unique, strong password for every online service. This prevents a password stolen from one site from being used to compromise your other accounts.

Mitigation (for Service Providers)

To prevent similar breaches, online service providers must implement robust data protection controls.

1. Data Minimization: Only collect and store the user data that is absolutely necessary for the service to function.
2. Access Control: Implement strict access controls on databases and APIs containing user data. Apply the principle of least privilege to all employees and services. This aligns with M1026 - Privileged Account Management.
3. API Security: Regularly test all public-facing APIs for security vulnerabilities, including insecure direct object references (IDOR) and excessive data exposure flaws.
4. Database Security: Encrypt sensitive data like email addresses at rest. Continuously monitor databases for anomalous access patterns that could indicate a breach in progress.