CISA AA24-038A PRC Critical Infrastructure February 2024

Volt Typhoon has attempted to access hashed credentials from the LSASS process memory space.

Volt Typhoon has used ntds.util to create domain controller installation media containing usernames and password hashes.

Volt Typhoon has stolen files from a sensitive file server and the Active Directory database from targeted environments, and used Wevtutil to extract event log information.

Volt Typhoon has executed the Windows-native `vssadmin` command to create volume shadow copies.

Volt Typhoon has used `net start` to list running services.

Volt Typhoon has collected window title information from compromised systems.

Volt Typhoon has queried the Registry on compromised systems, `reg query hklm\software\`, for information on installed software including PuTTY.

Volt Typhoon has employed Ping to check network connectivity.

Volt Typhoon has moved laterally to the Domain Controller via RDP using a compromised account with domain administrator privileges.

Volt Typhoon has used the Ultimate Packer for Executables (UPX) to obfuscate the FRP client files BrightmetricAgent.exe and SMSvcService.ex) and the port scanning utility ScanLine.

Volt Typhoon has used public tools and executed the PowerShell command `Get-EventLog security -instanceid 4624` to identify associated user and computer account names.

Volt Typhoon has used legitimate looking filenames for compressed copies of the ntds.dit database and used names including cisco_up.exe, cl64.exe, vm3dservice.exe, watchdogd.exe, Win.exe, WmiPreSV.exe, and WmiPrvSE.exe for the Earthworm and Fast Reverse Proxy tools.

Volt Typhoon has used commercial tools, LOTL utilities, and appliances already present on the system for network service discovery.

Volt Typhoon has leveraged WMIC for execution, remote system discovery, and to create and use temporary directories.

Volt Typhoon has created and accessed a file named rult3uil.log on compromised domain controllers to capture keypresses and command execution.

Volt Typhoon has enumerated running processes on targeted systems including through the use of Tasklist.

Volt Typhoon has used PowerShell including for remote system discovery.

Volt Typhoon has used the Windows command line to perform hands-on-keyboard activities in targeted environments including for discovery.

Volt Typhoon has used Brightmetricagent.exe which contains a command- line interface (CLI) library that can leverage command shells including Z Shell (zsh).

Volt Typhoon has gained initial access by exploiting privilege escalation vulnerabilities in the operating system or network services.

Volt Typhoon has used commercial tools, LOTL utilities, and appliances already present on the system for group and user discovery.

Volt Typhoon has run `rd /S` to delete their working directories and deleted systeminfo.dat from `C:\Users\Public\Documentsfiles`.

Volt Typhoon relies primarily on valid credentials for persistence.

Volt Typhoon has used compromised domain accounts to authenticate to devices on compromised networks.

Volt Typhoon has enumerated directories containing vulnerability testing and cyber related content and facilities data such as construction drawings.

Volt Typhoon has executed `net user` and `quser` to enumerate local account information.

Volt Typhoon has used compromised devices and customized versions of open source tools such as FRP (Fast Reverse Proxy), Earthworm, and Impacket to proxy network traffic.

Volt Typhoon has used the built-in netsh `port proxy` command to create proxies on compromised systems to facilitate access.

Volt Typhoon has used multi-hop proxies for command-and-control infrastructure.

Volt Typhoon has downloaded an outdated version of comsvcs.dll to a compromised domain controller in a non-standard folder.

Volt Typhoon has used `netsh` to create a PortProxy Registry modification on a compromised server running the Paessler Router Traffic Grapher (PRTG).

Volt Typhoon has obtained a screenshot of the victim's system using the gdi32.dll and gdiplus.dll libraries.

Volt Typhoon has obtained victim's screen dimension and display device information.

Volt Typhoon has obtained the victim's system timezone.

Volt Typhoon has used VPNs to connect to victim environments and enable post-exploitation actions.

Volt Typhoon has gained initial access through exploitation of multiple vulnerabilities in internet-facing software and appliances such as Fortinet, Ivanti (formerly Pulse Secure), NETGEAR, Citrix, and Cisco.

Volt Typhoon has targeted the browsing history of network administrators.

Volt Typhoon has used native tools and processes including living off the land binaries or “LOLBins" to maintain and expand access to the victim networks.

Volt Typhoon has queried the Registry on compromised systems for information on installed software.

Volt Typhoon has obtained credentials insecurely stored on targeted network appliances.

Volt Typhoon has accessed a Local State file that contains the AES key used to encrypt passwords stored in the Chrome browser.

Volt Typhoon has targeted network administrator browser data including browsing history and stored credentials.

Volt Typhoon has archived the ntds.dit database as a multi-volume password-protected archive with 7-Zip.

Volt Typhoon has compromised Virtual Private Servers (VPS) to proxy C2 traffic.

Volt Typhoon has used compromised Paessler Router Traffic Grapher (PRTG) servers from other organizations for C2.

Volt Typhoon has used compromised Cisco and NETGEAR end-of-life SOHO routers implanted with KV Botnet malware to support operations.

Volt Typhoon has exploited zero-day vulnerabilities for initial access.

Volt Typhoon has used legitimate network and forensic tools and customized versions of open-source tools for C2.

Volt Typhoon has used publicly available exploit code for initial access.

Volt Typhoon has gathered victim identify information during pre-compromise reconnaissance.