Amnon Kushnir, Director of Incident Response at Sygnia and expert in threat analysis, dives into the chilling activities of the Velvet Ant threat group. He reveals how they exploited a zero-day vulnerability in Cisco Nexus switches to deploy stealthy malware known as VelvetShell. The discussion emphasizes the challenges of detecting such advanced threats in enterprise networks. Kushnir also shares insights on improving security measures and the importance of community collaboration in combating cyber threats.
The Velvet Ant threat group demonstrates advanced cyber espionage tactics by exploiting zero-day vulnerabilities to infiltrate and manipulate Cisco Nexus switches.
Organizations must enhance monitoring and logging of overlooked devices to strengthen security against sophisticated threats like Velvet Ant's operations.
Deep dives
Overview of VelvetAnt Threat Group
VelvetAnt is identified as a potential China Nexus state-sponsored threat actor, primarily engaged in espionage activities against large corporate entities. This group's operations have been observed using known malicious tools, such as PlugX and ShadowPad, which are typically associated with Chinese cyber operations. They exhibit a high level of adaptability, shifting their tactics in response to detection and escalating their operation to utilize advanced methods, including zero-day exploits. This flexibility allows them to target not only traditional systems but also specialized network devices like Cisco Nexus switches, demonstrating their sophistication in cyber espionage.
Technical Tactics and Malware Deployment
VelvetAnt's operations on Cisco Nexus switches involve sophisticated techniques, including exploiting a zero-day vulnerability to execute commands at the Linux operating system level beneath the NXOS management interface. This capability allows them to deploy malware, specifically a variant known as VelvetShell, which is crafted from open-source tools that facilitate remote command execution and data tunneling through the compromised switch. The strategic use of less common versions of these tools enables the group to mask their activities, preventing typical logging mechanisms from recording their operations. Such stealthy tactics not only enhance their evasiveness but also expand their control over network segments.
Recommendations for Organizational Security
Organizations should recognize the importance of monitoring devices that are typically overlooked, such as Cisco Nexus switches, for security vulnerabilities beyond standard operational metrics. Implementing two-way monitoring protocols, enabling detailed logging, and conducting periodic threat hunts are critical steps for maintaining visibility over these devices. Given VelvetAnt's ability to avoid detection, establishing robust security measures and maintaining communication with vendors for log analysis is essential in case of suspected compromises. Engaging with cybersecurity experts can aid organizations in identifying unconventional activities and improving their overall defense against advanced persistent threats.
This week, we are joined by, Amnon Kushnir from Sygnia, who is sharing their work on "China-Nexus Threat Group ‘Velvet Ant’ Leverages a Zero-Day to Deploy Malware on Cisco Nexus Switches." In early 2024, Sygnia observed the ‘Velvet Ant’ threat group exploiting a zero-day vulnerability (CVE-2024-20399) to infiltrate Cisco Switch appliances and operate undetected within enterprise networks.
This attack enables threat actors to escape Cisco’s command interface and install malware directly on the device’s OS, bypassing standard security tools. The incident underscores the risks posed by third-party appliances and the importance of enhanced monitoring and threat detection to counter advanced persistent threats.