Analysis Summary

The China-linked threat actor Silk Typhoon (formerly Hafnium), known for exploiting Microsoft Exchange vulnerabilities in 2021, has evolved its tactics, now targeting the IT supply chain to gain initial access to corporate networks. According to a report, the group now focuses on remote management tools, cloud applications, and IT infrastructure to infiltrate organizations worldwide.

Once a victim is compromised, Silk Typhoon uses stolen API keys and credentials to escalate privileges and move laterally across networks, particularly targeting state and local governments, managed service providers (MSPs), healthcare, legal services, higher education, and defense sectors. The group exploits zero-day vulnerabilities in Ivanti Pulse Connect VPN (CVE-2025-0282), Palo Alto Networks firewalls (CVE-2024-3400), and Citrix NetScaler (CVE-2023-3519), among others, leveraging these flaws to execute remote code and infiltrate cloud environments.

Since late 2024, Silk Typhoon has increasingly focused on privileged access management (PAM) abuse, using OAuth applications with administrative permissions to extract sensitive data from email, OneDrive, and SharePoint via the MSGraph API. The group is also known for employing password spray attacks using enterprise credentials found in leaked public repositories.

To maintain persistence, Silk Typhoon deploys various web shells for command execution and data exfiltration. Additionally, they operate a "CovertNetwork" infrastructure that relies on compromised Cyberoam appliances, Zyxel routers, and QNAP devices to obfuscate their malicious activity.

Microsoft’s findings indicate that Silk Typhoon is a well-resourced and technically proficient group, continuously refining its techniques to exploit both on-premises and cloud environments. Their focus on supply chain attacks and cloud-based compromises underscores the growing complexity of state-sponsored cyber threats, necessitating enhanced security monitoring, credential management, and zero-trust strategies across affected sectors.

Impact

• Cyber Espionage
• Financial and Reputational Loss
• Credential Theft

Indicators of Compromise

CVE

• CVE-2025-0282

• CVE-2024-3400

• CVE-2023-3519

Remediation

• Implement multi-factor authentication (MFA) for all privileged and user accounts.
• Regularly rotate API keys and credentials to prevent unauthorized access.
• Restrict OAuth application permissions and monitor for suspicious third-party integrations.
• Enforce least privilege access for both cloud and on-premise environments.
• Apply security patches for Ivanti Pulse Connect VPN (CVE-2025-0282), Palo Alto Networks (CVE-2024-3400), Citrix NetScaler (CVE-2023-3519), and Microsoft Exchange vulnerabilities.
• Conduct regular vulnerability assessments and penetration testing to identify security gaps.
• Deploy Endpoint Detection & Response (EDR) solutions to detect and mitigate malicious activities.
• Enable cloud security monitoring tools such as Microsoft Defender for Cloud, AWS GuardDuty, or Google Chronicle.
• Set up alerts for unusual OAuth consent requests, API activity, and privilege escalations.
• Restrict OneDrive, SharePoint, and email API access to only verified applications.
• Segment networks to limit lateral movement between on-premise and cloud environments.
• Deploy Intrusion Detection and Prevention Systems (IDS/IPS) to detect and block malicious activity.
• Block malicious IPs, domains, and Silk Typhoon’s command-and-control (C2) infrastructure.
• Implement Advanced Threat Protection (ATP) to defend against phishing attacks and malicious emails.
• Train employees to recognize phishing attempts, suspicious login activities, and social engineering tactics.
• Use sandboxing and URL filtering to block access to malicious links and attachments.
• Develop and test an incident response plan to quickly contain and remediate breaches.
• Conduct regular threat hunting exercises to detect web shell usage, credential abuse, and supply chain compromises.
• Maintain isolated backups of critical data to mitigate ransomware risks and data theft.