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Mustang Panda Upgrades CoolClient With a Kernel Rootkit
Mustang Panda's updated CoolClient backdoor deploys a signed kernel driver to hide processes, files and network activity in Asian intrusions.
Kaspersky analysis shows Mustang Panda (HoneyMyte) upgraded its CoolClient espionage backdoor with a signed kernel-mode driver installed as a Windows service, communicating via IOCTL requests to hide processes, files and registry entries. In a Myanmar campaign the actor deployed PlugX first, then CoolClient via a fake Windows Defender directory and Sangfor defender.exe DLL sideloading, with scheduled task and AutoRun persistence and UAC bypass. The updated variant was observed in intrusions across Pakistan, Mongolia and Myanmar, with victims also in Russia including confirmed government entities.
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Mustang Panda Adds Signed Windows Rootkit to CoolClient Backdoor for Stealth
Kaspersky reports Mustang Panda's updated CoolClient backdoor now deploys a signed kernel-mode Windows rootkit, hitting government victims in Myanmar, Mongolia, Pakistan, and Russia.
Kaspersky identified a new CoolClient variant attributed to HoneyMyte (Mustang Panda) that installs a digitally signed Windows kernel driver, msagent.sys, to hide and protect malicious processes, files, registry keys, and C2 network information. CoolClient is consistently deployed as a secondary backdoor after PlugX, with confirmed victims including government entities in Myanmar, Mongolia, Pakistan, and Russia. In a Myanmar campaign, PlugX was used to deploy CoolClient via a renamed Sangfor executable for DLL side-loading, a scheduled task for persistence, and RPC-based process creation with PPID spoofing. The driver, signed with a 2013 certificate issued to Nanjing Ranyi Technology, implements 33 IOCTL handlers, process hiding via unlinking, a filesystem minifilter, and registry callbacks.
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APT group HoneyMyte upgrades CoolClient: the backdoor gets a kernel-level Windows rootkit
Kaspersky reports APT group HoneyMyte upgraded its CoolClient backdoor with a kernel-mode Windows rootkit hiding processes, files, and network connections.
Kaspersky researchers discovered a new variant of the HoneyMyte CoolClient backdoor equipped with a kernel-mode Windows rootkit driver. The rootkit hides malicious processes, files, and network connections from security tools and threat analysts, significantly increasing the backdoor's stealth. The report documents an upgrade to the APT group's backdoor tooling with a kernel-level implant.
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Operation QUICSILVER Targets Myanmar Government and IT with QUICAgent Backdoor
Seqrite Labs details Operation QUICSILVER, a China-nexus espionage campaign targeting Myanmar government and IT with graduation-invite lures deploying QUICAgent backdoor.
Seqrite Labs reported Operation QUICSILVER, a cyber espionage campaign against Myanmar's government and IT sectors attributed with moderate confidence to a China-nexus actor. Since April 2026, attacks used fake Belgian-Myanmar holiday and Burmese graduation ceremony invitation lures delivered via VHD/LNK files that abuse ftp.exe (LOLBAS) to assemble and launch QUICAgent, a Go backdoor communicating over QUIC on UDP 443 with five commands and Startup-folder persistence. Separately, China-linked Mustang Panda was observed using an updated COOLCLIENT backdoor with a signed kernel-mode driver across Myanmar, Mongolia, Pakistan, and Russia.
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Risky Bulletin: The EU publishes its upcoming cybersecurity standards
ETSI releases 17 draft cybersecurity standards vendors must meet when the EU Cyber Resilience Act takes effect in December 2027.
The European Telecommunications Standards Institute published 17 interim draft standards covering operating systems, routers, firewalls, VPNs, SIEMs, browsers, password managers, smart home devices, toys and wearables. They mandate basic security features such as post-sale updates, shipped SBOMs, modern cryptography and secure-by-default settings; public comments run until November, with final versions expected in December, one year before CRA compliance begins in December 2027. The newsletter also reports Irregular taking responsibility for AI test-environment escapes involving Anthropic and Meta frontier models, a breach at France's tax agency exposing 678,000+ citizens' data claimed by hacker ZeroBytes, and Kazakhstan eGov data covering 15 million citizens listed for sale on an underground forum. Additional briefs cover a $3.2 million Harmony Protocol theft crashing the ONE token 40%, Columbus Police still restoring systems two years after ransomware, DDoS attacks on Threema's provider, and Ukraine's GUR claiming a cyberattack on Wildberries.
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Angry Birds: Toy Ghouls’ new toys
Kaspersky tracks ransomware group Toy Ghouls deploying new custom backdoors, mqtt-bird-agent and matrix-bird-agent, using HiveMQ MQTT and Element as C2 channels.
Kaspersky reports that Toy Ghouls (also known as Bearlyfy, Laboo.boo and Feral Wolf), a financially motivated group targeting Russian organizations since 2025, shifted from leaked Babuk and LockBit builders and public GitHub tools to its custom GenieLocker ransomware. In early July 2026 the group deployed two custom backdoors: mqtt-bird-agent 0.1.0 using the public HiveMQ MQTT broker as C2, and matrix-bird-agent 0.1.0 using the Element messenger. The backdoors are delivered via WinRM using Evil-WinRM and WinRM-fs, persist as Windows services, and encrypt their configuration with ChaCha20-Poly1305 keyed to the machine's MachineGuid registry value.
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Security Affairs newsletter Round 590 by Pierluigi Paganini
Weekly Security Affairs newsletter roundup aggregating top cybercrime, malware, APT and AI security stories including ExfilSquad, Kimwolf v7 and Kimsuky AI use.
This is the Round 590 weekly newsletter from Security Affairs, linking to the week's major stories rather than reporting a single incident. Headlines include ExfilSquad extortion, a 7.3M chess.com record leak, Kimwolf botnet v7, SharePoint exploitation after a public PoC, Kimsuky integrating AI, and China-linked autonomous-style attacks. It is a digest and promotional item with no standalone technical details.
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