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Silver Fox is a China-linked cybercrime threat actor, also tracked as Void Arachne, that has been active since at least 2022 and is strongly associated with the ValleyRAT/Winos 4.0 malware ecosystem. The group conducts phishing- and fake-installer-driven intrusions across Asia and has targeted organizations and individuals with tax, invoice, software-update, and business-themed lures. Reported victim sectors include industrial manufacturing, consulting, trade, transport, technology, education, and state-owned enterprises, with repeated activity against tax-related targets and corporate finance personnel. Silver Fox is notable for combining commodity-style social engineering with increasingly sophisticated post-compromise tradecraft. Observed techniques include DLL sideloading, bring your own vulnerable driver (BYOVD) for kernel-level security-tool tampering, process injection, scheduled-task and service-based persistence, registry-based payload storage, anti-analysis checks, NTDLL unhooking, and layered watchdog mechanisms that restore terminated components. Campaigns have used legitimate signed executables as sideloading hosts and have shown modular execution chains designed for resilience and payload swapping. The actor’s malware ecosystem prominently includes ValleyRAT, also known as Winos 4.0, a Gh0st RAT-derived remote access trojan used for persistent access and follow-on tasking. Additional malware and tooling linked to Silver Fox in reporting include MODBEACON, SafeRat, ABCDoor, RomulusLoader, SilentRunLoader, and malware clusters or loaders overlapping with DONUTLoader and UUIDLoader. Some reporting has discussed possible links to Atlas RAT or TA4922, but those relationships remain unconfirmed or only circumstantial and should be treated cautiously. Silver Fox has been observed targeting Japanese industrial manufacturing organizations with phishing-led ValleyRAT intrusions, Russian organizations in industrial, consulting, trade, and transport sectors with tax-themed lures, Indian taxpayers and finance-related targets through tax-season phishing operations, and Indonesian targets through tax-themed impersonation campaigns. The group has also been reported targeting technology organizations, education entities, and state-owned enterprises. Its operations indicate a dominant financial motivation, although some reporting characterizes parts of the activity as crossing into state-aligned or intelligence-adjacent collection. Known capabilities include credential theft, keylogging, data exfiltration, persistence, initial access via phishing and fake software distribution, privilege escalation, post-exploitation, defense evasion, DLL sideloading, BYOVD, and process injection. Silver Fox’s continued development of loaders, RATs, and evasion components indicates an adaptive and expanding malware ecosystem rather than a single static toolset.
Mallory correlates actor tradecraft and target patterns against your stack, your sector, and your geography. See overlap before they land.
Who, where, and (when attributed) which flag flies behind the operation. Pulled from open-source reporting and Mallory's analyst review.
Sectors the actor has been observed targeting.
Geographies tied to known operations.
Attributed origin per open-source reporting.
51 distinct techniques observed across reporting, grouped by tactic. Hover any cell for the evidence excerpt; click through for MITRE's full description.
30 malware families attributed to this actor across reporting.
25 additional families tracked in Mallory.
2 CVEs this actor has used in observed campaigns. 2 of them exploited in the wild.
The NsecSoft NSecKrnl driver, identified as CVE-2025-68947, is a signed kernel-mode driver that exposes functionality for arbitrary process termination. By exploiting this capability, the ransomware is able to terminate the processes of major EDR and antivirus products...
CVE-2023-52271 documents how an affected version of wsftprm.sys can be abused to terminate protected processes.
718 indicators attributed to this actor: domains, IPs, hashes, and other artifacts pulled from reporting. View more in app.
20 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Conducting BYOVD-enabled intrusion activity against a Japanese industrial manufacturing target to deploy ValleyRAT for persistent remote access and defense evasion.
Conducting BYOVD-enabled intrusion campaigns against industrial manufacturing targets in Japan, using phishing lures, DLL sideloading, defense evasion, persistence, and ValleyRAT for remote access.
Assessed as the likely operator or user of SafeRat in phishing campaigns using DLL sideloading loaders, with links to prior Silver Fox tooling and tradecraft including ValleyRat, AtlasRat, DonutLoader, and UUIDLoader. Campaigns used tax/invoice-themed ZIP lures, targeted victims in Asia, and included silent deployment of SunLogin RMM.
Mentioned as a possible but unconfirmed operator potentially linked to AtlasRAT based on circumstantial evidence.
Match sector + geo + tech-stack targeting against your real footprint.
Every observed MITRE ATT&CK technique, grouped by tactic.
Families this actor is known to deploy, with IOCs and behavior.
CVEs this actor has used in known campaigns.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Domains, IPs, and hashes tied to this actor, refreshed continuously.