Latest cybersecurity reporting from selected sources.

Microsoft says GigaWiper combines at least 3 malware families into one modular tool

Microsoft has taken apart a destructive Windows backdoor it calls GigaWiper. What stands out is how it is built: not one tool but three older destructive programs bolted into one, offered as commands the operator can choose from

GigaWiper, also tracked as BLUERABBIT, is a destructive backdoor that combines multiple wiping and ransomware-like capabilities into a single operational platform. This blog analyzes how the malware incorporates code from several previously separate malware families and provides guidance to help defenders detect and defend against similar threats. The post GigaWiper: Anatomy of a destructive backdoor assembled from multiple malware appeared first on Microsoft Security Blog.

Microsoft signed a malicious kernel driver, and now it's being used to kill security software in ransomware attacks.

Cybersecurity researchers have flagged a new malware artifact generated using DeepSeek that constructed a novel attack path combining "unrealistic browser-malware concepts with a real browser capability" to turn it into a working ransomware technique that runs entirely inside the browser on both Windows and Android devices

CISA confirms BlueHammer (CVE-2026-33825) is now used in ransomware attacks to gain SYSTEM privileges through Microsoft Defender. BlueHammer, tracked as CVE-2026-33825, has moved from proof-of-concept noise to real ransomware attacks in the wild, the US CISA confirms. BlueHammer allows attackers to escalate privileges locally in Microsoft Defender. The vulnerability, along with two other zero-days dubbed […]

CISA confirmed on Monday that ransomware gangs are now exploiting a Microsoft Defender privilege escalation vulnerability, dubbed BlueHammer, that has previously been abused in zero-day attacks. [...]

A coordinated law enforcement operation, in partnership with private sector companies, including Bitdefender, Bitsight, ESET, and Microsoft, has resulted in the takedown of criminal infrastructure powering Amadey and StealC

Threat actors associated with the DragonForce ransomware have been observed using a custom Go-based remote access trojan (RAT) called Backdoor.Turn to conceal command-and-control (C2) traffic inside Microsoft Teams relay infrastructure

DragonForce hid for months by routing malware traffic through Microsoft Teams infrastructure, masking C2 activity and evading network detection. DragonForce ransomware operators hit a major U.S. services firm and stayed hidden for one to two months by routing their command-and-control traffic through Microsoft’s own Teams relay servers. Symantec’s threat hunters tracked the custom backdoor they […]

Command and control traffic exploited a Teams visitor token to make malicious activity look legitimate to defenders

DragonForce ransomware used a custom malware named 'Backdoor.Turn' to hide command-and-control traffic inside Microsoft Teams relay infrastructure. [...]

Microsoft Threat Intelligence presents a comprehensive analysis of The Gentlemen, a Go-based ransomware deployed by affiliates of Storm-2697 that combines per-file ephemeral key encryption with an aggressive self-propagation module to deploy itself across an entire network using series of simultaneous lateral movement techniques per target. The post The Gentlemen ransomware: Dissecting a self-propagating Go encryptor appeared first on Microsoft Security Blog.

Microsoft on Tuesday said it disrupted a malware-signing-as-a-service (MSaaS) operation that weaponized the company's Artifact Signing system to deliver malicious code and conduct ransomware and other attacks, compromising thousands of machines and networks across the world

'Thousands' of US victims, including 12+ machines owned and operated by Redmond

Microsoft says it has disrupted a malware-signing-as-a-service (MSaaS) operation that abused the company's Artifact Signing service to generate fraudulent code-signing certificates used by ransomware gangs and other cybercriminals. [...]

Fox Tempest is a financially motivated threat actor operating a malware‑signing‑as‑a‑service (MSaaS) used by other cybercriminals, including Vanilla Tempest and Storm groups, to more effectively distribute malicious code, including ransomware. The post Exposing Fox Tempest: A malware-signing service operation appeared first on Microsoft Security Blog.

Fox Tempest, a financially-motivated threat group, allowed ransomware operators and other cybercriminals to slip malware-laced software past security controls. The post Microsoft disrupts cybercrime service that abused software verification systems en masse appeared first on CyberScoop.

Microsoft’s Digital Crimes Unit has taken down the infrastructure of Fox Tempest, a prolific cybercrime-enabling threat group

The MuddyWater Iranian hackers disguised their operations as a Chaos ransomware attack, relying on  Microsoft Teams social engineering to gain access and establish persistence. [...]