UAT

Talos assesses with high confidence that UAT-7810 is a China-nexus threat actor based on the infrastructure that it provides to secondary China-nexus APTs such as UAT-5918 . Open-source reporting has also illustrated overlapping tooling between UAT-5918 and UAT-7810. However, at this time, Talos considers UAT-5918 and UAT-7810 separate APT actors tasked with their own set of objectives and targets.

Talos’ latest findings on UAT-7810 indicate that the threat actor continues to develop their custom-made malware dubbed “SHORTLEASH” with a newer version already being developed and hosted on attacker-controlled infrastructure. We track this new version of SHORTLEASH as “LONGLEASH.”

Talos has also discovered two more previously unknown tools in UAT-7810's arsenal:

Talos’ findings also illustrate that UAT-7810 used at least four new servers to host a variety of minor variations of DOGLEASH to deploy against compromised targets. An additional JAVA-based (JAR package) backdoor that we track as “JARLEASH” was also deployed by UAT-7810 on at least one of the three servers for administration purposes, including file management, FTP, SFTP, and Netcat.

Talos has observed UAT-7810 primarily exploit known vulnerabilities in unpatched Ruckus wireless routers, a tactic UAT-7810 has used since 2025. CVEs exploited include:

Talos discovered four new servers being used by UAT-7810 to host malicious payloads for a variety of hardware platforms including MIPS, ARM, and x64. The malware hosted predominantly consists of DOGLEASH, and accompanying shell scripts are executed on compromised systems to download and execute DOGLEASH.

All three of the following IP addresses were associated with VPS instances that indicated UAT-7810 acquired and used these servers as download locations:

One of the IPs, “217.15.164[.]147”, was also used as infrastructure to conduct exploitation of ASUS’ AiCloud Routers in early 2026 — specifically CVE-2025-2492 — indicating that UAT-7810 or an associated threat actor likely attempted to expand their ORB network to AiCloud Routers.

The other two IPs (“194.233.92[.]26” and “217.15.164[.]147”) hosted a TLS server on port 99 with the certificate fingerprint:

Forensic analysis of compromised networking devices led to the discovery of a fourth IP address UAT-7810 used to host their malicious payloads: “95.182.100[.]231”, residing in Hong Kong.

LONGLEASH is a new version of UAT-7810's previously disclosed backdoor SHORTLEASH . SHORTLEASH consisted of a backdoor capable of contacting its command and control (C2), hosting a web server, managing tunnels, and acting as both a C2 server and client. LONGLEASH, however, contains a variety of additional capabilities, indicating that UAT-7810 is actively developing it for use against their targets.

LONGLEASH is built off the same codebase as SHORTLEASH, with both tools being internally named “ff-agent”. The LONGLEASH variant compiled for MIPS processors is built on the asynchronous version of the Boost library ( Boost.Asio ) to minimize the blocking time and maximize the performance of the network.

The internal name for the LONGLEASH project is “nz1.0” and it has the following major components:

The other major executor modules support managing of network connections to other servers, including TLS and public key infrastructure, managing clients connected to the implant, sockets and URIs.

The executor is also tasked with authorization of clients, routing of the messages through the proxy network, and setting and management of basic network tunnels.

Finally, the executor contains functionality to remove the implant and all traces from the server if a suspicious connection or tampering is detected.

The implant contains the User-Agent string "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.95 Safari/537.36" which may allow it to hide within legitimate traffic purporting to be an instance of the Windows Chrome version 122.

Apart from the Boost.Asio, the implant contains code from at least two open-source libraries: Nanopb, used for processing protobuf messages, and MbedTLS , for establishing TLS, proxying TLS encrypted communications, and managing x509 certificates for the network. The implant does not use a standard libc library but a small musl library libc that implements C functions on top of Linux syscalls.

LONGLEASH also has the capability to act as an intermediate C2 server. It can obtain commands and data from the original C2 and forward to its peers.

Talos also discovered a previously unknown backdoor, developed and operated by UAT-7810, that we track as DOGLEASH. After compromising a networking device, UAT-7810 deploys a shell script that:

DOGLEASH will bind and listen for an incoming request on a local hardcoded port. Any TCP data received is then decoded using a hardcoded password string. Based on the command code and accompanying data received, it creates a new thread in the process and carries out a specific action:

Execute command using /bin/sh -c

Rename file to create a backup

Close socket listener

Get OS info info -> release, version, machine HW ID, node name

Execute code in memory

JARLEASH is a JAR-based backdoor that UAT-7810 deploys on their own infrastructure, as well as on compromised systems with JAVA available, to enable easy access to the system. JARLEASH is accompanied by a startup script that first kills any active instances of JARLEASH on the system, and then spawns the JAVA container to deploy JARLEASH.

JARLEASH can either use an external configuration file or default to an embedded configuration. The configuration file contains in Simplified Chinese, indicating that the operators were Chinese-speaking individuals.

The backdoor has the following capabilities:

Talos also discovered a test binary UAT-7810 developed that we track as “LEASHTEST.” This binary is not malicious as-is, but its presence on a device likely indicates a compromise. It is used to test rudimentary functionality on the MIPS platform. Internally named "iot-test", it checks to see if it can take the following actions on an Internet-of-Things (IOT) device:

The development and use of LEASHTEST signifies that even though they have developed LONGLEASH, a full-fledged backdoor framework, UAT-7810 is still actively testing functionality on MIPS platforms and may not be completely confident of its behavior on MIPS devices.

SNORT® SIDs for the threats detailed here are: 66433, 66432, 66430, 66431, 301493.

ClamAV signatures for the malicious tooling associated with this cluster are:

Startup script for JARLEASH

Configuration file for JARLEASH