Throughout 2025, CrowdStrike has identified multiple intrusions targeting VMware vCenter environments at U.S.-based entities, in which newly identified China-nexus adversary WARP PANDA deployed BRICKSTORM malware. WARP PANDA exhibits a high level of technical sophistication, advanced operations security (OPSEC) skills, and extensive knowledge of cloud and virtual machine (VM) environments. In addition to BRICKSTORM, WARP PANDA has also deployed JSP web shells and two new implants for ESXi environments — now named Junction and GuestConduit — during their operations.

WARP PANDA demonstrates a high level of stealth and almost certainly focuses on maintaining persistent, long-term, covert access to compromised networks. Their operations are likely motivated by intelligence-collection requirements aligned with the strategic interests of the People’s Republic of China (PRC).

Details

During the summer of 2025, CrowdStrike identified multiple instances in which the adversary now tracked as WARP PANDA targeted VMware vCenter environments at U.S.-based legal, technology, and manufacturing entities.

WARP PANDA maintained long-term, persistent access to the compromised networks; in one of the intrusions, gaining initial access in late 2023. In addition to deploying JSP web shells and BRICKSTORM on VMware vCenter servers, the adversary also deployed two previously unobserved Golang-based implants — Junction and GuestConduit — on ESXi hosts and guest VMs, respectively.

WARP PANDA frequently gains initial access by exploiting internet-facing edge devices and subsequently pivots to vCenter environments, using valid credentials or exploiting vCenter vulnerabilities. To move laterally within the compromised networks, the adversary uses SSH and the privileged vCenter management account vpxuser.¹ In some instances, CrowdStrike identified them using the Secure File Transfer Protocol (SFTP) to move data between hosts.

Using tradecraft focused on stealth and OPSEC, WARP PANDA leverages TTPs that include log clearing and file timestomping, as well as creating malicious VMs² — unregistered in the vCenter server — and shutting them down after use. Similarly, in an attempt to blend in with legitimate network traffic, the adversary has used BRICKSTORM to tunnel traffic through vCenter servers, ESXi hosts, and guest VMs. BRICKSTORM implants masquerade as legitimate vCenter processes and have persistence mechanisms that allow the implants to survive after file deletion and system reboots.

On numerous occasions, CrowdStrike observed WARP PANDA staging data for exfiltration. The adversary used an ESXi-compatible version of 7-Zip to extract and stage data from thin-provisioned snapshots of live ESXi guest VMs. Separately, WARP PANDA leveraged 7-Zip to extract data from VM disks hosted on a non-ESXi Linux-based hypervisor. CrowdStrike Services also found evidence that the adversary used their access to vCenter servers to clone domain controller VMs, likely in an attempt to collect sensitive data such as the Active Directory Domain Services database.

WARP PANDA likely used their access to one of the compromised networks to engage in rudimentary reconnaissance against an Asia Pacific government entity. They also connected to various cybersecurity blogs and a Mandarin-language GitHub repository. Further, during at least one intrusion, the adversary specifically accessed email accounts of employees who work on topics that align with Chinese government interests.

Malware

BRICKSTORM

BRICKSTORM is a backdoor written in Golang that frequently masquerades as legitimate vCenter processes, such as updatemgr or vami-http.³ The implant has tunneling and file management capabilities allowing users to browse file systems and download or upload files.

BRICKSTORM uses WebSockets to communicate with command-and-control (C2) infrastructure over TLS and uses multiple methods to obfuscate C2 communications and circumvent network-monitoring measures. These methods include using DNS-over-HTTPS (DoH) to resolve C2 domains, creating multiple nested TLS channels for C2 sessions, and leveraging public cloud services such as Cloudflare Workers and Heroku for C2 infrastructure.⁴

Junction

Junction is a Golang-based implant for VMware ESXi servers that masquerades as a legitimate ESXi service by listening on port 8090, which is also used by the legitimate VMware service vvold. The implant acts as an HTTP server, listening for incoming requests, and has extensive capabilities that include executing commands, proxying network traffic, and communicating with guest VMs through VM sockets (VSOCK).

GuestConduit

GuestConduit is a Golang-based network traffic–tunneling implant that runs within a guest VM and establishes a VSOCK listener on port 5555. This implant facilitates communication between guest VMs and hypervisors. GuestConduit also parses JSON-formatted client requests to mirror or forward network traffic and likely is intended to work with Junction’s tunnelling commands.

Vulnerability Exploitation

WARP PANDA has exploited multiple vulnerabilities in edge devices and VMware vCenter environments during their operations  (Table 1).

Cloud Activity

WARP PANDA is a cloud-conscious adversary capable of moving laterally, accessing sensitive data, and establishing persistence in cloud environments.

In late summer 2025, the adversary exploited access to multiple entities’ Microsoft Azure environments, primarily to access Microsoft 365 data stored in OneDrive, SharePoint, and Exchange. In one instance, the adversary obtained user session tokens — likely by exfiltrating user browser files — and tunneled traffic through BRICKSTORM implants to access Microsoft 365 services via session replay. The adversary further accessed and downloaded sensitive SharePoint files related to an entity’s network engineering and incident response teams.

In at least one case, to establish persistence, the adversary registered a new multifactor authentication (MFA) device via an Authenticator app code after initially logging into a user account. In another intrusion, the adversary used the Microsoft Graph API to enumerate service principles, applications, users, directory roles, and emails.

Conclusion

Active since at least 2022, WARP PANDA is a cloud-conscious targeted intrusion adversary that exhibits advanced technical skills and distinct malware use. To date, WARP PANDA is the only adversary that CrowdStrike Intelligence has observed leveraging BRICKSTORM, GuestConduit, and Junction; however, industry reporting has noted that BRICKSTORM is possibly leveraged by multiple adjacent China-nexus actors.⁵

The adversary primarily targets entities in North America and consistently maintains persistent, covert access to compromised networks, likely to support intelligence-collection efforts aligned with PRC strategic interests.

WARP PANDA will likely maintain their intelligence-collection operations in the near to long term. This assessment is made with moderate confidence based on the adversary’s significant technical capabilities and focus on long-term access operations, which suggest they are associated with a well-resourced organization that has heavily invested in cyberespionage capabilities.

Recommendations

These recommendations can be implemented to help protect against the activity described in this blog post:

• Monitor for the creation of unsanctioned VMs; CrowdStrike Services offers a tool to identify unregistered VMware VMs⁶
• Retain and monitor ESXi and vCenter syslog via CrowdStrike Falcon® Next-Gen SIEM
• Audit unsanctioned outbound connections to unexpected network destinations and known command-and-control (C2) infrastructure associated with BRICKSTORM
• Consider disabling SSH access to VMware ESXi hosts
• Monitor for SSH authentications, specifically authentications as root and vpxuser
• Forward vSphere syslog to an external platform
• For daily administration, leverage local accounts using the principle of least privilege
• Enable ESXi’s execInstalledOnly enforcement setting
• For ESXi versions 8.0 or later, deactivate shell access for the vpxuser account on ESXi hosts
• Restrict outbound internet access from ESXi and vCenter
• Implement strict network segmentation and firewall rules for ESXi management interfaces
• Monitor and restrict nonstandard port usage on ESXi servers, particularly the use of port 8090 and other optional service ports
• Access vCenter only via an identity federation provider that mandates MFA
• Ensure EDR solutions are installed on guest VMs to detect potential tunneling activities
• Install security patches for vSphere infrastructure
• Enforce password policies and regular password rotation
• Regularly rotate administrative credentials and API keys

Appendix

Falcon LogScale Query

This CrowdStrike Falcon® LogScale query detects the activity described in this blog post. Network matches from VMware vSphere infrastructure should be investigated as a priority.

// Hunting rule for indicators

case { in(“SHA256HashData”,
values=[“40db68331cb52dd3ffa0698144d1e6919779ff432e2e80c058e41f7b93cec042”,
“88db1d63dbd18469136bf9980858eb5fc0d4e41902bf3e4a8e08d7b6896654ed”,
“9a0e1b7a5f7793a8a5a62748b7aa4786d35fc38de607fb3bb8583ea2f7974806”,
“40992f53effc60f5e7edea632c48736ded9a2ca59fb4924eb6af0a078b74d557”]);
in(“RemoteAddressIP4”, values=[“149.28.120.31”, “208.83.233.14”]) } | table([cid, aid, #event_simpleName, ComputerName])

Indicators of Compromise

This table details the IOCs related to the information provided in this blog post.

MITRE ATT&CK

This table details the tactics and techniques described in this blog post.

¹ The vpxuser account is native to vCenter-managed ESXi hosts. The account’s password is random, managed by vCenter, and unique for each ESXi host. Automatically changed on a regular basis, the password is stored in an encrypted form on the vCenter server. The account should only be used by vCenter to manage ESXi. Any evidence of SSH activity using this account should be thoroughly investigated, as such activity is likely malicious.

² https[:]//github[.]com/CrowdStrike/VirtualGHOST

³ https[:]//cloud[.]google[.]com/blog/topics/threat-intelligence/ivanti-post-exploitation-lateral-movement

⁴ https[:]//www[.]nviso[.]eu/blog/nviso-analyzes-brickstorm-espionage-backdoor

⁵ https[:]//cloud[.]google[.]com/blog/topics/threat-intelligence/brickstorm-espionage-campaign

⁶ https[:]//github[.]com/CrowdStrike/VirtualGHOST