Risky Bulletin: Expired cards can be used for new transactions
Researchers show expired Visa contactless cards can be revived via NFC man-in-the-middle relay to run fraudulent transactions; roundup also covers major breaches.
University of Massachusetts Amherst researchers built an NFC man-in-the-middle rig that updates a card's expiration date in transit and relays the modified payment to POS terminals, reviving expired contactless cards; Visa terminals and the backends of all five banks studied failed to catch the manipulation. The same roundup reports Iranian hackers shut down a small UK power plant for four days, Lazarus breached South Korea's Presidential Office as part of a campaign exceeding 100 victims, and French telecom SFR suffered a breach affecting over 2.1 million customers.
FBI raises alarm over deceptive phishing campaign targeting prominent people
The FBI warns of an ongoing OAuth consent phishing campaign granting attackers persistent access to high-profile victims' cloud accounts without passwords.
The FBI says attackers impersonate government officials, journalists and event coordinators on commercial messaging apps to trick prominent individuals, their families and acquaintances into authorizing malicious OAuth applications on Microsoft or Google cloud services. Once approved, attackers gain persistent access to emails, files and other sensitive data; the access survives password changes and bypasses MFA, and can only be revoked by invalidating the OAuth token in security settings. The campaign has been tracked since late 2025, and the FBI advises independently verifying senders and granting access only to trusted applications.
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.
Kimwolf botnet rebuilt to survive takedowns, researchers say
Palo Alto Unit 42 reports the Kimwolf/Aisuru botnet now uses HTTP/2 Chrome-impersonation floods and Ethereum blockchain-based command resolution to survive takedowns.
Palo Alto Networks' Unit 42 says a new Kimwolf/Aisuru botnet version active since February conducts DDoS floods over HTTP/2 with full Chrome browser fingerprints, making attack traffic hard to distinguish from real users. The malware resolves command servers via the Ethereum Name Service using five shuffled Ethereum endpoints, with a Tor hidden service fallback, so authorities cannot seize a domain or serve a takedown order. The botnet, powered mostly by hijacked Android TV boxes and IoT devices, previously had servers seized and an alleged operator arrested; new C2 infrastructure traces to a single network in Saint Petersburg, Russia. It is unclear whether the same developers built the new version.