Volt Typhoon, a China-government backed hacking group that has infiltrated America’s critical infrastructure networks for years, has consistently built and dismantled ephemeral malicious infrastructure to burrow into hundreds of sensitive systems undetected, Lumen Technologies’ Black Lotus Labs said in a Wednesday report.

The covert access operation that researchers call “Silent Train” isn’t a standalone network, but rather a series of compromised small office home office (SOHO) routers, internet of things (IoT) devices and enterprise infrastructure that Volt Typhoon has rapidly rotated through since late 2023. 

The Chinese threat group has used this chain of short-lived compromised infrastructure to exploit additional vulnerabilities, including zero-days, in network edge devices and gain deeper, persistent access into victim networks, researchers said. 

“Individual chains are assembled and dismantled every day, with infrastructure continually refreshed,” Michael Horka, principal information security engineer at Black Lotus Labs, told CyberScoop. “Volt Typhoon demonstrated a repeatable capability to rebuild a new chain with different infrastructure in less than two minutes, making the number of nodes at any one moment effectively close to zero.”

Black Lotus Labs has notified hundreds of victims since it first identified Silent Train activity, including telecom providers, government entities, defense contractors, communication services, universities and IT firms. Other victims spanning critical infrastructure include organizations in the water, energy, transportation, maritime, rail, aviation and emergency services sectors.

“The ephemeral nature of the framework means our observations should not be interpreted as a complete census of Volt Typhoon activity,” said Horka, who also was the lead researcher on the report.

The nation-state group’s investment in operational security and preserving access is remarkable, according to Black Lotus Labs.

“We observed infrastructure assembled in under two minutes, sessions averaging roughly four hours, extensive cleanup, compartmentalization and continued development of new access vectors,” Horka said. “That is considerable effort devoted not even to get into their end targets, but purely to making important operations difficult to discover and trace.”

Volt Typhoon relied more heavily on Silent Train after the FBI and Justice Department disrupted the KV Botnet in early 2024, researchers said. Earlier this year, U.S. and global authorities warned about a widespread shift in Chinese hacking groups’ use of covert networks riding on compromised common devices.

The reach of those efforts is extensive and ongoing. Volt Typhoon has exploited and abused more than 27 device classes in Silent Train operations, including edge devices, enterprise management tools, identity and access management systems, networking infrastructure and other technologies. 

“The diversity matters, but the discipline matters even more,” Horka said. “Specific device types were consistently reserved for particular positions in the chain. It operated less like a collection of randomly compromised devices and more like an organized inventory of capabilities.”

The threat group has successfully compromised devices and technologies from Fortinet, Cisco, ManageEngine, Ivanti, F5, Check Point, Palo Alto Networks, ServiceNow, TP-Link, Netgear and ArcGIS, researchers said. Black Lotus Labs also observed confirmed zero-day campaigns targeting Versa Director, N-Able N-Central, Cisco Catalyst SD-WAN and VeloCloud Orchestrator. 

“The exploitation patterns, victimology, and geographic targeting observed throughout our investigation point to a sustained focus on communications, defense, government, and critical infrastructure environments of enduring strategic value,” Black Lotus Labs researchers wrote in the report. “Through repeated targeting of centralized management platforms and control-plane technologies, Silent Train shows how Volt Typhoon systematically pursues and preserves access to some of the most consequential networks in the United States.”

Silent Train’s ephemerality and operational discipline means it can’t be measured in size. These attributes also make it “fundamentally difficult to disrupt because there isn’t one network to take down,” Horka said. 

“What exists today will be completely different tomorrow,” he added. “You can try to remove individual pieces, but removing the actor’s ability to continuously rebuild them is a much harder problem to solve.”

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ISSUE 23.34 • 2026-08-24 ON SECURITY By Susan Bradley It all started when I was assisting someone who was trying to determine whether their Wi-Fi mesh routers were operating at the best possible speed. I tried to log in to the Web-based interface to the mesh system, which indicated that browser access was disabled. Uh-oh. […]

PUBLIC DEFENDER By Brian Livingston Public water utilities in several US states were hit with coordinated hacker attacks on July 26–27, 2026. The intrusions temporarily knocked Internet-connected control devices offline, forcing some agencies to warn customers to boil tap water. No permanent poisonings occurred, but the exploits may be a hacker group’s test run or […]

ON SECURITY By Susan Bradley OpenAI’s recent attack on another company’s cloud instances reminds me that sometimes we forget the basics. As we understand the situation at the moment, OpenAI’s test platform was meant to be isolated and not connected to the Internet. But because it needed to download certain items, it was given read-only […]

Russian state-sponsored hackers are breaking into critical infrastructure around the world by exploiting poorly configured and vulnerable networking devices, authorities from the United States and 12 additional countries said in a joint cybersecurity advisory Monday.

Officials once again urged defenders to take more preventative measures to thwart attacks from the Russian Federal Security Service Center 16, which has been actively targeting critical infrastructure for more than a decade. The hackers are also tracked as Berserk Bear, Energetic Bear, Crouching Yeti, Dragonfly, Ghost Blizzard and Static Tundra.

“This is an ongoing issue that has impacted various U.S. and foreign networks across multiple sectors, including the defense industrial base, communications, energy, financial services, government facilities and health care sectors,” the National Security Agency said in a statement.

The state-sponsored attackers scan the internet for vulnerable routers using default or weak passwords, and have also exploited vulnerabilities in Cisco devices, Cisco’s Smart Install feature and web portals to take over network devices. 

Two of the Cisco vulnerabilities exploited by the Russian FSB Center 16 hackers are quite old, including CVE-2008-4128 and CVE-2018-0171. 

Officials shared technical details of the threat group’s activities and advised network defenders to disable Cisco Smart Install on all devices, use stronger modes of authentication and passwords, monitor for unusual credentials and logins using local accounts. 

The joint advisory comes nearly a year after the FBI issued a similar alert about the same group targeting end-of-life networking devices running Cisco Smart Install. 

On Monday, the European Union blamed Russia’s FSB Center 16 for a December 2025 attack on Poland’s energy grid. The United Kingdom, also on Monday, sanctioned 24 individuals and entities allegedly involved in various attacks attributed to Russian intelligence services.

“From directing criminals to targeting businesses, and striking Poland’s energy grid in the depths of winter, the Russian state is sinking to new lows in its attempts to undermine European security,” Yvette Cooper, foreign security of the United Kingdom, said in a statement. 

Other countries behind the joint cybersecurity advisory include: Canada, Australia, New Zealand, Czech Republic, Denmark, Estonia, Finland, France, Italy, Poland and Sweden.

The post Officials once again warn defenders that Russian hackers are targeting network devices appeared first on CyberScoop.

NETWORKING By Simon Bisson Small Office/Home Office (SOHO) routers are more secure than you think — although they could do with a little help from their friends. Way back when we used dial-up to connect to the Internet, software firewalls such as ZoneAlarm were all we needed to protect our PCs — because slow-speed connections […]

Ethan Robish // In this series of posts, I’ll discuss how I segmented my home network using VLANs and how I moved away from using a risky consumer-grade router at […]

The post Home Network Design – Part 1 appeared first on Black Hills Information Security, Inc..