Grandoreiro Resurfaces in Mexico With New DLL Sideloading Campaign
Banking trojan Grandoreiro resurfaces in Mexico using DLL sideloading, now accounting for 40% of detections after its 2024 disruption.
Grandoreiro, a banking trojan disrupted in 2024, is active again with a new DLL sideloading technique. Mexico now accounts for 40% of the malware's detections. The resurgence signals renewed targeting of banking customers in Latin America.
ValleyRAT: When Legitimate Software Becomes a Malware Delivery Tool
Kaspersky details ValleyRAT delivered via trojanized QN Wallpaper using DLL sideloading, tied to Silver Fox and hitting 1,500+ users in China and India.
Kaspersky found a malicious installer abusing a modified version of the legitimate QN Wallpaper adware application to deliver the ValleyRAT backdoor via DLL sideloading of libcef.dll. The installer masquerades as DingTalk, Chrome or Tencent Meeting software, creates persistence, disables Windows Defender via the DisableAntiSpyware registry key, and loads AES-encrypted payloads. ValleyRAT collects keystrokes, clipboard contents and screenshots plus system details, can download additional modules, and resists removal by injecting into svchost.exe or marking its process critical. The campaign was detected over 100,000 times in 2026, affecting more than 1,500 users mainly in China and India, and is attributed to Silver Fox with both espionage and financial motives.
BambooToken Malware Uses MQTT to Control Windows and Linux Systems
Lumen uncovers BambooToken, a stealthy multi-platform malware using MQTT C2 and Tendyron DLL sideloading to compromise Asian and South American organizations.
Lumen Black Lotus Labs disclosed BambooToken, a previously undocumented malware family active since at least February 2023 that controls Windows and (since December 2025) Linux hosts via the MQTT protocol for C2. The malware sideloads a rogue OnKeyToken_KEB.dll via Tendyron's OnKey PKI token software, gathers host details, and uses a WMI-based plugin to enumerate installed antivirus products and exfiltrate them to C2 domains proxied through Cloudflare. A dozen compromised entities were detected across Asia and South America, and DLL sideloading plus SoftEther VPN usage suggests a China nexus.
ValleyRAT Backdoor Hides in Signed Adware That Users Add to Antivirus Exclusions
Silver Fox distributes ValleyRAT via signed QN Wallpaper adware, sideloading a malicious libcef.dll into a trusted process to evade defenses.
Kaspersky reports the Silver Fox threat actor disguising the ValleyRAT backdoor (Winos 4.0) inside a modified, signed copy of the QN Wallpaper adware tool, using DLL sideloading to run within a trusted process. The installer disables Windows Defender via the DisableAntiSpyware registry key, adds autorun entries, and elevates via runas when needed; ValleyRAT steals keystrokes, clipboard data, and screenshots and can mark its process critical to trigger BSOD if killed. Kaspersky recorded more than 100,000 ValleyRAT detections affecting over 1,500 unique users in 2026, mostly in China and India, with prior campaigns against Japan, India, and Russia.
PAPERMILL Malware Campaign Abuses Signed Notepad++ to Deliver VenomRAT to Windows Users
JUMPSEC tracks PAPERMILL, a China-nexus phishing campaign using a signed Notepad++ binary, libcurl.dll sideloading, and Donut loaders to deploy VenomRAT against Indian tax-audit targets.
PAPERMILL delivers ISO disk images via tax-audit phishing emails that passed SPF, DKIM, and DMARC, containing a renamed Authenticode-signed Notepad++ executable and a malicious libcurl.dll that proxies curl functions while executing loader logic in DllMain. The chain uses Mark-of-the-Web bypasses, anti-sandbox sleeps, UAC elevation prompts, Registry persistence, and a Donut shellcode loader to reflectively load .NET VenomRAT v6.0.3 with HVNC and credential-stealing capability, with C2 at 154.36.188.201:4449. JUMPSEC assesses the campaign as China-nexus, financially motivated, and Silver Fox-adjacent rather than definitively Silver Fox-operated.
BambooToken: The Malware That Speaks MQTT to Stay Under the Radar
Lumen's Black Lotus Labs uncovered BambooToken, a Windows and Linux malware family using MQTT broker-based C2 and DLL sideloading across Asia since February 2023.
Lumen Black Lotus Labs identified BambooToken, a multiplatform malware family that exchanges commands through MQTT brokers so infected hosts never contact the C2 server directly, active from at least February 2023 through July 2026. The Windows variant sideloads via Tendyron's OnKey hardware-token software used in Chinese banking and government, or impersonates Kingsoft Office, without either vendor's signing certificate being compromised; a Linux build appeared by December 2025 with shell, file transfer, and system information commands. Victims include MikroTik and DrayTek routers in Singapore, Cambodia, and Vietnam reached after internet-wide SNMP scanning, and Lumen cannot attribute the family to any known actor.
Spark RAT Targets Cambodia, Abuses Vulnerable OPSWAT Driver to Disable Security Tools
Acronis details a Spark RAT campaign against Cambodia abusing the vulnerable OPSWAT ardrv.sys driver (CVE-2026-36425) to disable Microsoft Defender and other security tools.
Acronis TRU analyzed a multi-stage Spark RAT campaign targeting Cambodian individuals and organizations with lures spanning government notices, public health materials, and real estate documents. Attack chains use phishing emails with Inno Setup archives, DLL side-loading via a signed Tencent executable, and BYOVD abuse of the vulnerable OPSWAT ardrv.sys driver (CVE-2026-36425) to terminate security software. Shellcode hidden in PNG files patches AMSI and ETW, establishes scheduled task and service persistence, and injects into vssvc.exe and ctfmon.exe to run the open-source Go-based Spark RAT. Tactics resemble the Silver Fox actor, but Acronis tracks the cluster as unattributed with low confidence.
BraZetsu Malware Turns Compromised Windows Hosts Into Criminal Marketplace Inventory
Group-IB details BraZetsu, a modular Python Windows malware that monetizes compromised-host access through the Infected Marketplace for initial access brokers.
Group-IB attributes BraZetsu to the Exilware threat actor, believed to be native Portuguese speakers targeting Iberian and Latin American e-commerce, financial, industrial, and law enforcement victims. The framework, first observed in early May 2026, uses generative AI for data triage and target prioritization, steals browser histories and digital certificates, and hunts Brazilian CNAB financial remittance files. Access to compromised hosts is sold on the Infected Marketplace from roughly $5.80, letting buyers remotely deploy secondary payloads over WebSocket-linked infrastructure. Some samples evaded detection on VirusTotal; delivery likely uses VBS loaders from a domain also used to distribute the Ousaban banking trojan.
Tracking OceanLotus’ new Downloader, KerrDown
Unit 42 identifies KerrDown, a new OceanLotus (APT32) downloader active since 2018 targeting Vietnamese speakers via malicious macros and DLL side-loading.
Unit 42 tracks KerrDown, a previously undocumented downloader family used by OceanLotus (APT32) since at least early 2018, primarily targeting Vietnam or Vietnamese-speaking individuals. Delivery uses macro-laced Microsoft Office documents embedding base64-encoded 32-bit and 64-bit DLLs, and RAR archives containing a legitimate program abused for DLL side-loading. KerrDown is dropped as main_background.png, downloads a DES-encrypted payload from a URL, and executes it directly in memory. Researchers used Jaccard-index similarity analysis to identify the new family, connect campaign samples, and infer patterns in the group's working hours and days.
ClearFake WebDAV infection chain delivers Amatera stealer, ZigCryptoStealer, and NetSupport Manager
Cisco Talos details ClearFake WebDAV chains delivering Amatera stealer to a Ukrainian government organization, with cryptocurrency and credential theft payloads.
Cisco Talos investigated DLL executions named 'verification.google' via WebDAV UNC paths at a Ukrainian government organization, tracking the actor as UAT-10820 and assessing with moderate confidence the activity is Russian and opportunistic rather than targeted. The infection chain uses ClearFake JavaScript injected via a Cloudflare Worker, EtherHiding storage on BNB Smart Chain contracts, and a ClickFix fake Google CAPTCHA prompt to deliver Amatera stealer. Secondary payloads differ by C2: one loader deploys ZigCryptoStealer with a Go reverse TCP proxy and a vulnerable driver that kills EDR, while the other installs an unauthorized NetSupport Manager with a Russia-based C2. Similar Amatera chains were separately documented by Malwarebytes and Blackpoint Cyber, but with no shared infrastructure.