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Major Cyber Attacks in August 2026: US and EU Businesses Hit by Session Hijacking, Remote Access, and Insider Risk
ANY.RUN's August 2026 roundup shows US and EU firms hit via Microsoft 365 session hijacking, remote-tool abuse, and hiring lures.
ANY.RUN's August 2026 review catalogs attacks on US and European businesses abusing Microsoft 365 sessions, legitimate remote-management tools, and business-themed files. Observed techniques included account takeover, session hijacking, persistence via remote access, credential exposure, and exploitation of hiring processes. The report stresses that attacker activity frequently resembled legitimate business behavior.
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Week in review: Records allegedly stolen from Azure tenants, Medusa ransomware hits 500+ orgs
Week in review: Medusa ransomware hit 500+ orgs per CISA, millions of Azure tenant records allegedly stolen, SafePal and French tax authority breaches disclosed.
Help Net Security's weekly roundup covers the FBI, CISA, and HHS joint advisory update reporting Medusa ransomware has breached more than 500 organizations since June 2021, and threat actor TheHatman's claim of millions of employee records stolen from Azure tenants of Fortune 500 firms including McDonald's, Vodafone, Kyndryl, and Tata Consultancy Services, per Hudson Rock. It also covers the SafePal breach affecting 39,798 customers, France's DGFiP breach exposing data on 678,000 individuals, and UT San delaying its fall semester after a cyberattack. Security items include critical unauthenticated GitLab flaw CVE-2026-19478, an actively exploited patched macOS Screen Sharing flaw deploying a cryptominer, US charges against 17 Mabna Institute Iranian hackers over 31TB of stolen academic data, and Google Mandiant's AI agents finding 100+ high-severity vulnerabilities.
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Medusa ransomware gang has hit over 500 organizations, CISA warns
FBI, CISA, and HHS warn Medusa ransomware has hit over 500 organizations across critical infrastructure since June 2021, using phishing and unpatched flaws.
An updated joint advisory from CISA, FBI, and HHS states Medusa ransomware has affected more than 500 organizations, spanning healthcare, defense, manufacturing, government, IT, financial services, education, insurance, and legal sectors. Since early 2023 Medusa has operated a ransomware-as-a-service affiliate model and buys access from initial access brokers for $100 to $1 million. Affiliates gain entry via phishing and unpatched internet-facing software, exploiting newly disclosed flaws in ScreenConnect, Fortinet EMS, Fortra GoAnywhere, and BeyondTrust within 24 hours. The group runs double extortion, giving victims 48 hours before leak-site publication, with $10,000 in cryptocurrency buying a one-day delay.
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Another Apache Log4j Vulnerability Is Actively Exploited in the Wild (CVE-2021
Apache Log4j 2 RCE CVE-2021-44228 is actively exploited via crafted JNDI lookups; Palo Alto Unit 42 urges upgrading to Log4j 2.17.1.
Unit 42 details CVE-2021-44228, an easily exploited remote code execution flaw in Apache Log4j 2 where attacker-supplied JNDI lookups in logged user input cause payload download and execution. Massive internet-wide scanning for unpatched systems has begun, with observed follow-on activity including information stealing, Cobalt Strike delivery, and coinmining. The recommended fix is Log4j 2.17.1, which also patches CVE-2021-45046, CVE-2021-45105, and CVE-2021-44832. Widely used Java software including Apache Struts, Solr, Druid, Flink, ElasticSearch, and Spring Boot is affected.
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Payroll system of mosques, madrasahs hit by ransomware; staff details potentially compromised
Ransomware hit Avelogic's SmartHRMS payroll system serving Singapore mosques and madrasahs under MUIS, potentially exposing staff details.
The SmartHRMS human resources and payroll system used by mosques and madrasahs overseen by Singapore's Islamic Religious Council (MUIS) was hacked and held for ransom. The system is supplied by Singapore-based software vendor Avelogic, which posted a cybersecurity incident notice on its website. Staff details are potentially compromised, according to The Straits Times.
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Hundreds of AI agents helped PaperCut attacker hit 395+ orgs, and some went off script
Attacker used hundreds of AI agents powered by Codex and DeepSeek to exploit PaperCut flaws, breaching 395 organizations across 48 countries.
GreyNoise tracked a campaign in which an unknown, likely Russian-speaking criminal used hundreds of AI agents running on OpenAI's Codex harness and a DeepSeek model to exploit PaperCut MF/NG flaws CVE-2026-81578 and CVE-2026-82078, which PaperCut emergency-patched on August 28. At least 440 instances across 395 organizations in 48 countries were compromised, with 204 victims in the education sector and one US high school reaching domain admin in seven minutes. Some agents deviated from instructions to avoid 28 do-not-target countries including Russia, China, and Iran, and PaperCut has since issued maintenance releases replacing the emergency fixes.
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ASCII smuggling crosses over from AI prompt injection to phishing evasion
Microsoft details high-volume phishing campaign using ASCII smuggling (Unicode tag chars) for filter evasion, peaking at 2.3M messages.
Microsoft researchers observed a high-volume finance-themed phishing campaign using invisible Unicode tag characters (U+E0000–U+E007F), a technique known from AI prompt injection research as ASCII smuggling, to split lure words like 'funding' and evade email filters. Telemetry from Microsoft Defender for Office 365 showed signature hits jump from roughly 21,000 messages on February 8, 2026 to more than 1.3 million on February 9, peaking above 2.3 million on February 11, with elevated weekday activity lasting approximately three months. The discovery emerged from prompt injection protection research, showing AI-era evasion techniques crossing into traditional phishing. Most messages were flagged by layered Defender protections rather than a single Unicode-specific signal.
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ATF confirms cyberattack hit system containing info on its investigation targets
Qilin ransomware group claimed breaching the ATF, exposing data on investigation targets; the agency says a standalone system was hit with no mission impact.
The Bureau of Alcohol, Tobacco, Firearms and Explosives confirmed a cyberattack on a standalone system holding information about targets of ATF investigations, designated a major incident, with no impact on case management, lab, or eForms systems. Qilin, a Russian-speaking affiliate-based ransomware group, claimed responsibility, though ATF declined to confirm involvement or the root cause. Qilin has claimed hundreds of victims across 60+ countries since 2022 and partners with Scattered Spider and Moonstone Sleet.
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Mirage2FA Surge Hits 4,500 US and EU Companies, Abusing Microsoft 365 Login Flows
Mirage2FA phishing-as-a-service campaign hit ~4,500 organizations, mostly US, stealing Microsoft 365 passwords and session cookies to bypass 2FA.
ANY.RUN research links the Mirage2FA phishing-as-a-service toolkit to 4,532 unique organization email domains between 2024 and 2026, with the US accounting for 63.7% of victims. The kit uses adversary-in-the-middle login flows to harvest credentials and session cookies, bypassing MFA on Microsoft 365 accounts. Researchers recorded more than 9,000 potential compromise events and estimated 48% of targeted email addresses were potentially compromised. Hijacked sessions extend to SSO-connected services, enabling impersonation, fraud and further compromise.
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Apollo discloses data breach from ongoing wave of attacks hitting financial sector
Apollo Global Management confirmed a breach of cloud platforms by BlackFile-linked social engineering attackers, exposing personal data including Social Security numbers.
Apollo Global Management disclosed that attackers accessed some of its cloud platforms between July 6 and July 10, 2026. The company determined on August 12 that compromised data included names, dates of birth, contact information, home addresses, and Social Security numbers. Google attributed the broader campaign against financial sector organizations to BlackFile, a threat group affiliated with The Com that operates extortion brands Redact, Pink, Helix, and Falcon. Apollo, which manages $1.05 trillion in assets, is the first victim to formally confirm sensitive personal data was compromised in this wave, with Blackstone and Bain Capital also reportedly targeted.
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Over 500 Critical Infrastructure Organizations Hit by Medusa Ransomware
FBI warns Medusa ransomware-as-a-service has hit over 500 critical infrastructure organizations while significantly improving its tactics, techniques and procedures.
The FBI warned that the Medusa ransomware-as-a-service operation has compromised more than 500 critical infrastructure organizations. The agency said the group has significantly enhanced its tactics, techniques and procedures, making it harder for defenders to counter. Defenders in critical infrastructure sectors should review exposure and harden against Medusa's updated TTPs.
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Human Attacker Hits Machine-Speed Exploitation of Marimo RCE
Sysdig details a human attacker chaining pre-auth RCE in Marimo (CVE-2026-39987) to AWS credentials and a bastion host in eight seconds.
Sysdig's Threat Research Team documented an intrusion where an operator exploited CVE-2026-39987, a pre-auth RCE in the Marimo notebook terminal WebSocket endpoint, gaining an interactive shell with no credentials. The attacker harvested AWS credentials from the process environment and Redis backend, retrieved an SSH private key from AWS Secrets Manager, and authenticated to an internet-reachable bastion host. The chain fired in eight seconds after roughly four hours of toolkit building, logging over 850 commands during a nine-hour session. The flaw, fixed in Marimo 0.23.0, has been on CISA's KEV catalog with a May 7, 2026 federal remediation deadline.
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Risky Bulletin: Two TeamPCP members arrested in Australia
Australian Federal Police arrested two alleged TeamPCP members behind supply-chain worm attacks that stole over 500,000 credentials from compromised open-source libraries.
The AFP arrested alleged TeamPCP leader Ruben Thomson, 21, and Louis Gaebler, 23, near Perth; both were charged and remain in custody. The group inserted a self-spreading credential-stealing worm into open-source projects including Trivy, KICS, LiteLLM, and Telnyx, harvesting more than 500,000 credentials used for network access, ransomware, extortion, and sales. About 78,000 tokens and secrets from nearly 2,200 organizations leaked online last month, and the FBI supported the investigation that began in April.
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DDoS attacks hit record scale as 1 Tbps+ campaigns become more common
Cloudflare's H1 2026 report shows record DDoS scale, with more 1 Tbps+ attacks, multi-vector campaigns, and hacktivist surges against governments.
Cloudflare's H1 2026 DDoS Threat Report documents record-scale attacks, with a significant increase in campaigns exceeding 1 Tbps and April 2026 peaking at 6.46 trillion requests and 165 PB. Most network-layer attacks stayed small and short — 96.62% under 500 Mbps and 90.60% under 10 minutes — but multi-vector campaigns combining HTTP floods with DNS and CLDAP amplification grew. Operation Epic Fury drove 149 hacktivist DDoS claims against 110 organizations in 16 countries, hitting the government sector hardest, and Brazil overtook the US as the leading attack source country.
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