Insights

New Guidance Released on Microsoft Exchange Server Security Best Practices

Today, CISA, in partnership with the National Security Agency and international cybersecurity partners, released Microsoft Exchange Server Security Best Practices, a guide to help network defenders harden on-premises Exchange servers against exploitation by malicious actors. Threat activity targeting Exchange continues to persist, and organizations with unprotected or misconfigured Exchange servers remain at high risk of compromise.  Best practices in this guide focus on hardening user authentication and access, ensuring strong network encryption, and minimizing application…

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Aisuru Botnet Shifts from DDoS to Residential Proxies

Aisuru, the botnet responsible for a series of record-smashing distributed denial-of-service (DDoS) attacks this year, recently was overhauled to support a more low-key, lucrative and sustainable business: Renting hundreds of thousands of infected Internet of Things (IoT) devices to proxy services that help cybercriminals anonymize their traffic. Experts say a glut of proxies from Aisuru and other sources is fueling large-scale data harvesting efforts tied to various artificial intelligence (AI) projects, helping content scrapers evade…

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Microsoft Releases Out-of-Band Security Update to Mitigate Windows Server Update Service Vulnerability, CVE-2025-59287

Microsoft released an update to address a critical remote code execution vulnerability impacting Windows Server Update Service (WSUS) in Windows Server (2012, 2016, 2019, 2022, and 2025), CVE-2025-59287, that a prior update did not fully mitigate.  CISA strongly urges organizations to implement Microsoft’s updated Windows Server Update Service (WSUS) Remote Code Execution Vulnerability guidance, 1 or risk an unauthenticated actor achieving remote code execution with system privileges. Immediate actions for organizations with affected products are:…

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Canada Fines Cybercrime Friendly Cryptomus $176M

Financial regulators in Canada this week levied $176 million in fines against Cryptomus, a digital payments platform that supports dozens of Russian cryptocurrency exchanges and websites hawking cybercrime services. The penalties for violating Canada’s anti money-laundering laws come ten months after KrebsOnSecurity noted that Cryptomus’s Vancouver street address was home to dozens of foreign currency dealers, money transfer businesses, and cryptocurrency exchanges — none of which were physically located there. On October 16, the Financial…

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CISA Releases 10 Industrial Control Systems Advisories

CISA released 10 Industrial Control Systems (ICS) advisories. These advisories provide timely information about current security issues, vulnerabilities, and exploits surrounding ICS. ICSA-25-294-01 Rockwell Automation 1783-NATR ICSA-25-294-02 Rockwell Automation Compact GuardLogix 5370 ICSA-25-294-03 Siemens SIMATIC S7-1200 CPU V1/V2 Devices ICSA-25-294-04 Siemens RUGGEDCOM ROS Devices ICSA-25-294-05 CloudEdge Online Cameras and App ICSA-25-294-06 Raisecomm RAX701-GC Series ICSMA-25-294-01 Oxford Nanopore Technologies MinKNOW ICSA-25-035-07 Schneider Electric Pro-Face GP-Pro EX and Remote HMI (Update A) ICSA-24-354-07 Schneider Electric Modicon Controllers…

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Email Bombs Exploit Lax Authentication in Zendesk

Cybercriminals are abusing a widespread lack of authentication in the customer service platform Zendesk to flood targeted email inboxes with menacing messages that come from hundreds of Zendesk corporate customers simultaneously. Zendesk is an automated help desk service designed to make it simple for people to contact companies for customer support issues. Earlier this week, KrebsOnSecurity started receiving thousands of ticket creation notification messages through Zendesk in rapid succession, each bearing the name of different…

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CISA Directs Federal Agencies to Mitigate Vulnerabilities in F5 Devices

Today, CISA issued Emergency Directive ED 26-01: Mitigate Vulnerabilities in F5 Devices to direct Federal Civilian Executive Branch agencies to inventory F5 BIG-IP products, evaluate if the networked management interfaces are accessible from the public internet, and apply newly released updates from F5.  A nation-state affiliated cyber threat actor has compromised F5 systems and exfiltrated data, including portions of the BIG-IP proprietary source code and vulnerability information, which provides the actor with a technical advantage…

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Patch Tuesday, October 2025 ‘End of 10’ Edition

Microsoft today released software updates to plug a whopping 172 security holes in its Windows operating systems, including at least two vulnerabilities that are already being actively exploited. October’s Patch Tuesday also marks the final month that Microsoft will ship security updates for Windows 10 systems. If you’re running a Windows 10 PC and you’re unable or unwilling to migrate to Windows 11, read on for other options. The first zero-day bug addressed this month…

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DDoS Botnet Aisuru Blankets US ISPs in Record DDoS

The world’s largest and most disruptive botnet is now drawing a majority of its firepower from compromised Internet-of-Things (IoT) devices hosted on U.S. Internet providers like AT&T, Comcast and Verizon, new evidence suggests. Experts say the heavy concentration of infected devices at U.S. providers is complicating efforts to limit collateral damage from the botnet’s attacks, which shattered previous records this week with a brief traffic flood that clocked in at nearly 30 trillion bits of…

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ShinyHunters Wage Broad Corporate Extortion Spree

A cybercriminal group that used voice phishing attacks to siphon more than a billion records from Salesforce customers earlier this year has launched a website that threatens to publish data stolen from dozens of Fortune 500 firms if they refuse to pay a ransom. The group also claimed responsibility for a recent breach involving Discord user data, and for stealing terabytes of sensitive files from thousands of customers of the enterprise software maker Red Hat.…

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