Fake Software Installers Disable Windows Update and Weaken Microsoft Defender

An active malware campaign is using bogus software-download websites to impersonate trusted vendors and distribute malicious installers. "The campaign has targeted users looking to download popular software and has resulted in compromises across multiple organizations and industries, primarily...

ValleyRAT Backdoor Hides in Signed Adware That Users Add to Antivirus Exclusions

The threat actor known as Silver Fox has been observed distributing the ValleyRAT backdoor disguised as a signed Chinese adware application, running the malware under a trusted process to slip past users who add such software to their antivirus exclusions. Russian cybersecurity vendor Kaspersky...

ValleyRAT masquerading as adware

Attackers typically try to pass off malware as legitimate applications or as potentially unwanted programs that users deliberately search for and download, such as cheats or cracks. They often rely on ad and affiliate networks to deliver their creations to victims' devices. This post examines a...

China-Linked TA4922 Expands Phishing Attacks to U.K., Germany, Italy, and South Africa

A new China-linked cybercrime group known as TA4922 has expanded its targeting focus to target European organizations in the U.K., Germany, Italy, and South Africa. These efforts have been complemented by a "rapid operational tempo" and a continually evolving malware arsenal comprising known...

Silver Fox Deploys ABCDoor Malware via Tax-Themed Phishing in India and Russia

The China-based cybercrime group known as Silver Fox aka Monarch, SwimSnake, The Great Thief of Valley, UTG-Q-1000, and Void Arachne has been linked to a new campaign targeting organizations in Russia and India with a new malware called ABCDoor. The activity involved using phishing emails that...

Silver Fox uses the new ABCDoor backdoor to target organizations in Russia and India

In December 2025, we detected a wave of malicious emails designed to look like official correspondence from the Indian tax service. A few weeks later, in January 2026, a similar campaign began targeting Russian organizations. We have attributed this activity to the Silver Fox threat group. Both...

A week in security (February 23 – March 1)

Last week on Malwarebytes Labs: Public Google API keys can be used to expose Gemini AI data Inside a fake Google security check that becomes a browser RAT Fake Zoom and Google Meet scams install Teramind: A technical deep dive How to understand and avoid Advanced Persistent Threats The Conduent...

Fake Huorong security site infects users with ValleyRAT

A convincing lookalike of the popular Huorong Security antivirus has been used to deliver ValleyRAT, a sophisticated Remote Access Trojan RAT built on the Winos4.0 framework, to users who believed they were improving their security. The campaign, attributed to the Silver Fox APT group—a...

Silver Fox Targets Indian Users With Tax-Themed Emails Delivering ValleyRAT Malware

The threat actor known as Silver Fox has turned its focus to India, using income tax-themed lures in phishing campaigns to distribute a modular remote access trojan called ValleyRAT aka Winos 4.0. "This sophisticated attack leverages a complex kill chain involving DLL hijacking and the modular...

Silver Fox Uses Fake Microsoft Teams Installer to Spread ValleyRAT Malware in China

The threat actor known as Silver Fox has been spotted orchestrating a false flag operation to mimic a Russian threat group in attacks targeting organizations in China. The search engine optimization SEO poisoning campaign leverages Microsoft Teams lures to trick unsuspecting users into downloadin...

ValleyRAT Campaign Targets Job Seekers, Abuses Foxit PDF Reader for DLL Side-loading

Job seekers looking out for opportunities might instead find their personal devices compromised, as a ValleyRAT campaign propagated through email leverages Foxit PDF Reader for concealment and DLL side-loading for initial entry...

Silver Fox Expands Winos 4.0 Attacks to Japan and Malaysia via HoldingHands RAT

The threat actors behind a malware family known as Winos 4.0 aka ValleyRAT have expanded their targeting footprint from China and Taiwan to target Japan and Malaysia with another remote access trojan RAT tracked as HoldingHands RAT aka Gh0stBins. "The campaign relied on phishing emails with PDFs...

HiddenGh0st, Winos and kkRAT Exploit SEO, GitHub Pages in Chinese Malware Attacks

Chinese-speaking users are the target of a search engine optimization SEO poisoning campaign that uses fake software sites to distribute malware. "The attackers manipulated search rankings with SEO plugins and registered lookalike domains that closely mimicked legitimate software sites," Fortinet...

HiddenGh0st, Winos and kkRAT Exploit SEO, GitHub Pages in Chinese Malware Attacks

Chinese-speaking users are the target of a search engine optimization SEO poisoning campaign that uses fake software sites to distribute malware. "The attackers manipulated search rankings with SEO plugins and registered lookalike domains that closely mimicked legitimate software sites," Fortinet...

Silver Fox APT Exploits Signed Windows Driver to Deliver ValleyRAT

Check Point reports Silver Fox APT using a signed WatchDog driver flaw to disable Windows security and deliver…...

Silver Fox Exploits Microsoft-Signed WatchDog Driver to Deploy ValleyRAT Malware

The threat actor known as Silver Fox has been attributed to abuse of a previously unknown vulnerable driver associated with WatchDog Anti-malware as part of a Bring Your Own Vulnerable Driver BYOVD attack aimed at disarming security solutions installed on compromised hosts. The vulnerable driver ...

Silver Fox Exploits Microsoft-Signed WatchDog Driver to Deploy ValleyRAT Malware

The threat actor known as Silver Fox has been attributed to abuse of a previously unknown vulnerable driver associated with WatchDog Anti-malware as part of a Bring Your Own Vulnerable Driver BYOVD attack aimed at disarming security solutions installed on compromised hosts. The vulnerable driver ...

Hackers Use Fake VPN and Browser NSIS Installers to Deliver Winos 4.0 Malware

Cybersecurity researchers have disclosed a malware campaign that uses fake software installers masquerading as popular tools like LetsVPN and QQ Browser to deliver the Winos 4.0 framework. The campaign, first detected by Rapid7 in February 2025, involves the use of a multi-stage, memory-resident...

Silver Fox APT Hides ValleyRAT in Trojanized Medical Imaging Software

Chinese Silver Fox APT exploits trojanized medical imaging software to spread ValleyRAT malware, posing a serious threat to…...

Fake Google Chrome Sites Distribute ValleyRAT Malware via DLL Hijacking

Bogus websites advertising Google Chrome have been used to distribute malicious installers for a remote access trojan called ValleyRAT. The malware, first detected in 2023, is attributed to a threat actor tracked as Silver Fox, with prior attack campaigns primarily targeting Chinese-speaking...