Executive Summary

Volt Typhoon, a China-linked APT group, has been using a covert network called Silent Train to hide zero-day attacks on critical systems. Lumen's Black Lotus Labs has tracked this network for three years and linked it to at least four zero-days. This threat is actively exploited, and security teams should take immediate action.

Technical Analysis

Volt Typhoon uses disposable relay chains, known as Silent Train, to conceal their zero-day attacks. This tactic allows them to hide their attack infrastructure and evade detection. The Silent Train network has been linked to at least four zero-day vulnerabilities, but specific details about these vulnerabilities are not provided.

How It Gets Exploited

Volt Typhoon's exploitation involves using the Silent Train network to hide their attack infrastructure. The attacker starts by establishing a foothold in the target network, likely through a phishing campaign or exploitation of a previously unknown vulnerability. Once inside, they deploy the Silent Train relay chains to conceal their communication with the compromised systems. This allows them to maintain a covert presence and exploit zero-day vulnerabilities without being detected.

Impact Assessment

The impact of these zero-day attacks is significant, as they can allow attackers to gain unauthorized access to critical systems, steal sensitive information, or disrupt operations. The fact that Volt Typhoon has been actively exploiting these vulnerabilities means that the threat is current and ongoing. Unfortunately, no CVSS score is provided, but based on the severity of the attacks and the covert nature of the Silent Train network, a high severity level is assumed.

Recommended Actions

  • Investigate and block Silent Train infrastructure to prevent exploitation.
  • Implement robust monitoring and detection capabilities to identify potential zero-day attacks.
  • Ensure timely patching and vulnerability management to reduce the attack surface.
  • Enhance threat intelligence and stay informed about Volt Typhoon's tactics, techniques, and procedures (TTPs).

Sources

  • Security Affairs: https://securityaffairs.com/202023/intelligence/volt-typhoon-used-silent-train-to-hide-zero-day-attacks.html