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Microsoft Secure

Poisoned peer-to-peer app kicked off Dofoil coin miner outbreak

On March 7, we reported that a massive Dofoil campaign attempted to install malicious cryptocurrency miners on hundreds of thousands of computers. Windows Defender Antivirus, with its behavior monitoring, machine learning technologies, and layered approach to security detected and blocked the attack within milliseconds. Windows 10 S, a special configuration of Windows 10 providing Microsoft-verified security,...

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Behavior monitoring combined with machine learning spoils a massive Dofoil coin mining campaign

Update: Further analysis of this campaign points to a poisoned update for a peer-to-peer (P2P) application. For more information, read Poisoned peer-to-peer app kicked off Dofoil coin miner outbreak. Just before noon on March 6 (PST), Windows Defender Antivirus blocked more than 80,000 instances of several sophisticated trojans that exhibited advanced cross-process injection techniques, persistence...

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A worthy upgrade: Next-gen security on Windows 10 proves resilient against ransomware outbreaks in 2017

Adopting reliable attack methods and techniques borrowed from more evolved threat types, ransomware attained new levels of reach and damage in 2017. The following trends characterize the ransomware narrative in the past year: Three global outbreaks showed the force of ransomware in making real-world impact, affecting corporate networks and bringing down critical services like hospitals,...

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Detonating a bad rabbit: Windows Defender Antivirus and layered machine learning defenses

Windows Defender Antivirus uses a layered approach to protection: tiers of advanced automation and machine learning models evaluate files in order to reach a verdict on suspected malware. While Windows Defender AV detects a vast majority of new malware files at first sight, we always strive to further close the gap between malware release and...

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Microsoft Contact: Stephen Smith (stepsmit)
Agency: Cinco Design
Agency Contact: Kate Callahan (
Photographer: Amy Sacka (
Shoot month: March 2017
Location: Portland, OR
Business: LinkedIn Datacenter

Windows Defender ATP machine learning and AMSI: Unearthing script-based attacks that ‘live off the land’

Scripts are becoming the weapon of choice of sophisticated activity groups responsible for targeted attacks as well as malware authors who indiscriminately deploy commodity threats. Scripting engines such as JavaScript, VBScript, and PowerShell offer tremendous benefits to attackers. They run through legitimate processes and are perfect tools for “living off the land”—staying away from the...

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Detecting reflective DLL loading with Windows Defender ATP

Today’s attacks put emphasis on leaving little, if any, forensic evidence to maintain stealth and achieve persistence. Attackers use methods that allow exploits to stay resident within an exploited process or migrate to a long-lived process without ever creating or relying on a file on disk. In recent blogs we described how attackers use basic...

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Windows Defender ATP machine learning: Detecting new and unusual breach activity

Microsoft has been investing heavily in next-generation security technologies. These technologies use our ability to consolidate large sets of data and build intelligent systems that learn from that data. These machine learning (ML) systems flag and surface threats that would otherwise remain unnoticed amidst the continuous hum of billions of normal events and the inability...

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Antivirus evolved

Some say antivirus is an outdated technology. What does “antivirus” even mean? For us, antivirus is the most commonly recognized term that means for customers “a product that stops bad programs from infecting my device.” Saying “antivirus” is similar to when you hear a Southerner (like myself) say “Coke” when referring to a carbonated beverage....

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Combating a spate of Java malware with machine learning in real-time

In recent weeks, we have seen a surge in emails carrying fresh malicious Java (.jar) malware that use new techniques to evade antivirus protection. But with our research team’s automated expert systems and machine learning models, Windows 10 PCs get real-time protection against these latest threats. Attackers are constantly changing their methods and tools. We...

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