Volt Typhoon targets US

Volt Typhoon targets US critical infrastructure with living-off-the-land techniques

@ducklah @ndma 29 May 2023

Description

Microsoft has uncovered stealthy and targeted malicious activity focused on post-compromise credential access and network system discovery aimed at critical infrastructure organizations in the United States. The attack is carried out by Volt Typhoon, a state-sponsored actor based in China that typically focuses on espionage and information gathering. Microsoft assesses with moderate confidence that this Volt Typhoon campaign is pursuing development of capabilities that could disrupt critical communications infrastructure between the United States and Asia region during future crises.

The threat actor puts strong emphasis on stealth in this campaign, relying almost exclusively on living-off-the-land techniques and hands-on-keyboard activity. They issue commands via the command line to (1) collect data, including credentials from local and network systems, (2) put the data into an archive file to stage it for exfiltration, and then (3) use the stolen valid credentials to maintain persistence. In addition, Volt Typhoon tries to blend into normal network activity by routing traffic through compromised small office and home office (SOHO) network equipment, including routers, firewalls, and VPN hardware. They have also been observed using custom versions of open-source tools to establish a command and control (C2) channel over proxy to further stay under the radar.

Their campaign targeting critical infrastructure providers, and their tactics for achieving and maintaining unauthorized access to target networks. Because this activity relies on valid accounts and living-off-the-land binaries (LOLBins), detecting and mitigating this attack could be challenging. Compromised accounts must be closed or changed.

Reference

https://www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/