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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.

ANY.RUN · 15d agoThreat actor in the wild1

BigBear 2.0 phishing campaign hijacks Microsoft 365 sessions after MFA

CloudSEK uncovered BigBear 2.0, a PhaaS operation that captured 4,148 Microsoft 365 session cookies, hijacking authenticated sessions after MFA via AiTM proxy.

CloudSEK infiltrated the BigBear 2.0 phishing-as-a-service panel in June, finding 5,137 credential records tied to 461 organizations in over 40 countries, including 4,148 captured session cookies and 474 completed post-MFA logins. The operation, built on Evilginx2, uses an attacker-controlled reverse proxy to steal authenticated session cookies and residential proxies to defeat location-based Conditional Access checks, while custom code disables FIDO2/WebAuthn on phishing pages. At least five affiliates operated 42 VPS nodes, with IT services and managed service providers the most targeted sector.

CSO Online · 8d agoPhishing & fraud in the wild1

Infostealers Are Hijacking Claude Sessions and Draining Subscriptions

Infostealers hijacked active Claude sessions to bypass 2FA, drain paid usage and run unauthorized charges; Anthropic is revoking sessions and refunding.

Anthropic confirmed that infostealer malware on user machines stole active Claude login sessions, letting attackers bypass passwords, MFA, and SSO and drain paid usage and run unauthorized charges. Affected families identified on Windows include Vidar, LummaC2, StealC, RedLine, and Acreed, plus Atomic Stealer on a small number of Macs; the malware typically arrived via unofficial downloads or malicious apps. Anthropic signed users out, removed saved payment cards, revoked affected sessions, and is refunding unauthorized charges, noting phones and tablets were not involved.

Security Affairs · 16d agoMalware in the wild

AmnesiaStealer Hijacks Chromium Sessions to Give Attackers Live Browser Control on macOS

Jamf details AmnesiaStealer, a new Rust-based macOS infostealer that hijacks Chromium sessions for live attacker-controlled browser access and steals Keychain data.

Jamf Threat Labs disclosed a three-stage macOS infostealer called AmnesiaStealer distributed via a fake GitHub download page using a ClickFix-style lure that tricks users into pasting a Base64 command into Terminal. The Rust payload harvests the Keychain, Apple Notes, Telegram sessions, Safari cookies, and 16 Chromium-family browsers, and captures the system password via a native prompt validated with dscl. A remotely fetched stream_module gives operators hidden, interactive browser control via the Chrome DevTools Protocol, streaming a live session at roughly 3fps. It persists via a root LaunchDaemon impersonating Apple's crash reporter and leverages the TCC bypass CVE-2020-9771 against macOS Catalina.

The Hacker News · Aug 15, 2026Malware in the wildCVE-2020-9771

Anthropic locks out Claude users after infostealers hijack login sessions

Anthropic invalidated Claude sessions compromised by infostealers such as Vidar, Lumma and Atomic Stealer, which steal browser cookies to bypass 2FA.

Anthropic began locking users out of Claude accounts after infostealer malware stole browser session cookies, letting attackers replay logins and bypass two-factor authentication. Identified malware includes Vidar, Lumma (LummaC2), StealC, RedLine and Acreed on Windows and Atomic Stealer (AMOS) on a small number of Macs. Anthropic signed affected users out, removed saved payment methods and refunded unauthorized charges. One affected user traced the infection to a pirated game downloaded from a Russian underground forum; the company advised victims to remove the malware before resetting passwords and re-enabling 2FA.

Help Net Security · 16d agoData breach in the wild1

Mirage2FA Hijacks Companies’ Microsoft 365 Sessions, with Over 4K Victims in the US

Mirage2FA phishing-as-a-service kit uses AiTM attacks to hijack Microsoft 365 sessions, with over 4,000 US victims.

ANY.RUN analyzed Mirage2FA, an active phishing-as-a-service toolkit that steals Microsoft 365 credentials and authenticated sessions through Adversary-in-the-Middle phishing pages. About 63.7% of identified victims are in the US, with Technology, Manufacturing, and Education the most targeted industries. Thousands of compromise events were recorded between 2024 and 2026.

ANY.RUN · 29d agoPhishing & fraud in the wild1

The Top 4 Threats We Found by Investigating Every Alert for a Quarter

Prophet Security's quarterly threat report finds identity attacks made up roughly half of confirmed malicious activity, with stolen authenticated sessions bypassing conditional access controls.

Between May 1 and July 31, 2026, Prophet Security investigated every alert in customer environments immediately on arrival; about 7% of completed investigations were confirmed malicious. Direct account/session attacks made up roughly 18% of confirmed activity, with replayed authenticated sessions bypassing conditional access since no re-authentication occurs. Infostealer activity affected about a quarter of investigated organizations, mostly delivered via browsers through compromised websites, malicious ads, sponsored search results and ClickFix fake CAPTCHA gates, with payloads including Lumma Stealer, Vidar, HijackLoader and AsyncRAT. Credential phishing was the largest category at about 28%, with adversary-in-the-middle relays revealed by seconds-long MFA approvals from distant countries and MFA fatigue attacks exploiting automatic unlock policies.

BleepingComputer · 6d agoThreat actor in the wild

BigBear 2.0 Evilginx2 Phishing Campaign Bypasses Microsoft 365 MFA With Session Cookie Theft

CloudSEK identified BigBear 2.0, an Evilginx2-based AiTM phishing operation stealing Microsoft 365 MFA session cookies, hitting 461 organizations across 40-plus countries.

The campaign proxies Microsoft sign-in pages to capture credentials and authenticated session cookies, enabling session replay into email, Teams, SharePoint, OneDrive, and connected SSO applications. CloudSEK's June 2026 discovery found 5,137 stolen records, 1,032 passwords, and 4,148 session cookies tied to 3,331 victim IPs, linked to operator 'General Boss' across 42 VPS nodes. The operation targeted IT services and managed service providers, used country-matched residential proxies, and involved at least five affiliates.

Cyber Security News · 8d agoPhishing & fraud in the wild1

Attacker Hijacks AI Coding Assistant Session, Spreads Shai-Hulud Across About 100 Repositories

Mandiant says an attacker hijacked an AI coding-assistant session at a SaaS provider and spread the Shai-Hulud worm across roughly 100 repositories, stealing secrets.

Mandiant's September 2026 report describes an attacker hijacking an active AI coding-assistant session at an unnamed SaaS provider, then getting a poisoned package recommendation accepted and installing an infostealer via a malicious PyPI package. The attacker stole GitHub OAuth tokens, deployed the self-spreading Shai-Hulud worm across approximately 100 internal repositories, and stole repository secrets and product source code. Poisoning a package in the company's official namespace caused a second employee to pull the compromised version and become infected. Mandiant recommends verifying AI-recommended dependencies against checksums and allowlists, keeping secrets out of extension reach, and routing dependency traffic through internal repositories.

The Hacker News · 4h agoData breach in the wild

Inside Knight Office, a New M365 AiTM Phishing Kit

Huntress details Knight Office, a new AiTM phishing kit stealing Microsoft 365 session tokens and registering attacker-controlled devices.

Huntress investigated an August 18, 2026 adversary-in-the-middle attack using the Knight Office phishing kit, which captured Microsoft 365 session tokens via a DocuSign-style lure routed through a Monday.com tracking link and a compromised Joomla site. After token capture, the actor enrolled an unauthorized host in Microsoft Entra ID and bound a Windows Hello for Business key credential to the account. The kit's operator console, found at IP 104.37.188.94, is built on Python Flask and hosts at least 25 .vu phishing domains. Telemetry links the kit to at least nine token-replay logins in two weeks and roughly 700 reported lure emails since April.

Huntress · 14d agoPhishing & fraud in the wild1

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.

The Hacker News · 22d agoPhishing & fraud in the wild

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.

GBHackers · 1d agoIndustry in the wild

PEEP Turns Chrome and Edge Into Post-Compromise Backdoors for Host Command Execution

SOCRadar disclosed PEEP, a post-exploitation Chromium extension toolkit that turns Chrome and Edge into host-level backdoors via native messaging and C2 polling.

SOCRadar researchers detailed PEEP, a Chromium-based post-exploitation toolkit masquerading as a 'Smart Bookmarks' extension injected directly into Chrome and Edge profiles by forging Secure Preferences integrity values, bypassing Web Store checks. A native-messaging host binary (nm_host.exe) extends the browser agent to host-level command execution, file management, credential theft, and session hijacking, while the extension polls C2 endpoints at 206.237.30.232 or xfjcc.fun every 30 seconds over plaintext HTTP and exfiltrates browsing history, cookies, and tab metadata. PEEP is derived from the open-source RedExt red teaming framework, adds PowerShell persistence scripts, and includes a Linux-targeting Python script, suggesting cross-platform intent. The activity is unattributed but contains Chinese-language artifacts; a C2 /health endpoint showed 34 agent entries and 10 active sessions.

The Hacker News · 9d agoMalware in the wild1

Adobe Commerce CVE-2026-71362 Comes Under Attack Shortly After Public Disclosure

Attackers began exploiting critical Adobe Commerce flaw CVE-2026-71362 (CVSS 9.1) for unauthenticated customer account takeover shortly after patch release.

Sansec blocked the first exploitation attempts of CVE-2026-71362 immediately after Adobe published its advisory. The flaw lets unauthenticated attackers switch a customer session to another customer account, hijacking accounts and accessing private data without credentials, admin privileges or user interaction. It affects Adobe Commerce, Commerce B2B and Magento Open Source versions through the July 2026 patches, and Adobe issued isolated patch files APSB26-92 fixing seven vulnerabilities, including stored cross-site scripting and authorization issues.

Security Affairs · Aug 13, 2026Exploit / PoC in the wildCVE-2026-71362

BigBear 2 PhaaS Campaign Steals 5000+ Microsoft Credentials

CloudSEK researchers found the BigBear 2.0 PhaaS kit, built on Evilginx2, has stolen over 5,100 Microsoft 365 credentials across 461 organizations in 40+ countries.

CloudSEK gained admin access to the BigBear 2.0 phishing-as-a-service panel, an Evilginx2-based adversary-in-the-middle platform operated by someone using the alias 'General Boss'. The team observed 3,331 unique victim IPs across more than 40 countries, 42 VPS nodes mostly on Vultr, and 5,137 credential records across 461 organizations, including 4,148 session cookies, 1,032 plaintext passwords, and 474 completed MFA-bypassed authentications. IT and managed service providers were the most targeted sector, raising supply-chain risk since their compromise can expose client infrastructure and privileged Azure AD access.

Infosecurity Magazine · 8d agoPhishing & fraud in the wild

Hackers Weaponize Agentic AI to Automate Reconnaissance, Exploitation and Post-Exploitation

Google GTIG reports threat actors using agentic AI to automate reconnaissance, exploit selection, and credential harvesting, compromising thousands of secrets.

Google Threat Intelligence Group's Q3 2026 AI Threat Tracker documents threat actors operationalizing agentic AI: in one Mandiant investigation, a financially motivated actor built and executed a credential-harvesting operation in under six hours, with an exposed 'Recon' framework managing more than 23,800 harvested secrets including cloud and AI-service API keys. A Chinese-speaking actor tracked as knaithe used a DeepSeek-powered Hermes Agent for automated reconnaissance and vulnerability enumeration, pivoting from Langflow to n8n and enabling manual exploitation of exposed Citrix NetScaler, Marimo, Apache Tomcat, and VPN infrastructure. Operators harvested Citrix session cookies from process memory to bypass MFA, obtained AWS credentials from compromised Marimo instances, and deployed the Go-based NKAbuse backdoor, with reported RCE and data exfiltration. Google notes fully autonomous end-to-end AI attack pipelines have not yet been observed in the wild.

GBHackers · 7d agoThreat actor in the wild2

Gunra Ransomware Exploits Fortinet FortiOS, FortiProxy Flaws to Breach Networks

CISA, FBI, and South Korean agencies warn Gunra ransomware, with 51 victims since April 2025, exploits Fortinet flaws for double-extortion attacks on critical infrastructure.

CISA, the FBI, and South Korean agencies warned of Gunra ransomware attacks targeting healthcare, financial services, government, and professional services worldwide. The Conti-derived operation exploits internet-facing Fortinet FortiOS and FortiProxy flaws CVE-2024-55591 and CVE-2025-24472 for initial access, then deploys double extortion with Salsa20/ChaCha20 encryption and publishes non-payers on a leak site within five to seven days. Ransomware.Live lists 51 victims since April 2025, mostly in South Korea, Brazil, Spain, Thailand, and Hong Kong. The group uses Impacket tools for SMB lateral movement and NTDS credential dumping, tampers with VDI authentication to accept a designated OTP value to bypass MFA, and launched a RaaS affiliate program in January 2026 under the new alias Golden Community.

The Hacker News · Aug 12, 2026Ransomware in the wildCVE-2024-55591CVE-2025-24472