Weekly Cybersecurity Newsletter – Top 50 Biggest Cybersecurity Stories of the Week
GBHackers weekly digest rounds up 50 stories including Microsoft's 973-CVE patch drop, exploited Cisco FMC flaws, and Claude agent attacks.
GBHackers' September 7-12, 2026 newsletter summarizes the 50 biggest cybersecurity stories of the week. Highlights include Microsoft patching a record 973 CVEs with two exploited zero-days, active exploitation of Cisco FMC, Check Point VPN and Ivanti flaws, China-linked crews chaining Chrome and Windows zero-days, AI agents mass-exploiting PaperCut to compromise 440 servers, and the emergence of Panzer cross-platform ransomware. It also covers Anthropic and OpenAI agentic AI incidents and CrowdStrike's SafeMind launch.
Hackers Favor US Eastern Business Hours in M365 Phishing Campaign
KnowBe4 tracked 29,785 phishing emails abusing Microsoft 365 Direct Send to spoof internal senders while timing sends to US Eastern business hours.
KnowBe4 Threat Lab observed 29,785 confirmed phishing emails between July and August 2026 abusing Microsoft 365's Direct Send feature, which lets devices and legacy apps send mail without a dedicated account. The emails appeared to come from trusted internal addresses such as HR or accounting, bypassing email gateways by connecting directly to Exchange Online MX endpoints, with activity peaking on Monday-Tuesday during US Eastern business hours and near-zero weekend volume. About 35% of the messages carried malicious attachments like fake invoices, voicemail alerts, and OneDrive shares, and 4,023 used reply-to addresses on different domains to capture employee responses. Researchers recommended strict DMARC enforcement, connector restrictions, DKIM signing, and checking for the 'X-MS-Exchange-Organization-AuthAs: Anonymous' Exchange header.
CISA Warns Water Utilities: Find Your Exposed PLCs Before Attackers Do
CISA urged water utilities to secure internet-exposed PLCs after July 2026 attacks compromised over 100 US water and wastewater systems, suspected Iran-linked.
CISA's exposure-reduction guidance, published August 21, follows July 2026 attacks in which threat actors remotely accessed PLCs connected directly through cellular modems, changed device IP addresses and passwords, and in some cases disabled alarms and shutdown processes without notifying operators. Iran is the suspected actor, though officials stopped short of formal attribution. CISA recommends routing remote access through centrally managed secure gateways, phishing-resistant MFA, unique credentials, and external scanning of industrial protocols such as Modbus, EtherNet/IP, DNP3, BACnet and OPC UA.