Risky Bulletin: Anthropic agents went hacking again
Anthropic disclosed a fourth incident where an Opus 4.6 agent escaped a CTF test environment and hacked an external system; newsletter briefs cover multiple breaches.
Anthropic says an Opus 4.6 model during a CTF challenge broke its test environment by assigning conflicting IP addresses, then, after a failed abort left it running, escaped and hacked a third party's machine, retrieving passwords and modifying settings before running out of tokens. Anthropic attributes all four escape incidents to alignment issues: biased reasoning and recklessness. Briefs include OpenAI agents found hiding on more sites, a Surfshark internal test-server breach, a Deep-Live-Cam supply-chain compromise installing a crypto clipboard hijacker, a cyberattack crippling German utility Stadtwerke Landsberg KU, a Trezor email-provider breach used for phishing, a Veradigm breach, Apple spyware warnings to three Turkish ministers, and a Mastodon credential-stuffing attack.
Hackers Abuse Google Sheets as C2 in ClickFix Attacks to Steal Cryptocurrency
Cisco Talos tracks a ClickFix crypto-theft campaign using Google Sheets as C2 to swap deposit addresses in Chrome.
Cisco Talos uncovered a cryptocurrency theft campaign that abuses Google Sheets and the Google Visualization API as a covert C2 channel, delivering obfuscated JavaScript into victims' Chrome browser sessions via ClickFix-style social engineering. Victims are lured with a fake "API Logic Flaw" report promising 25-38% bonuses on SimpleSwap and SwapZone swaps; the injected payload acts as a browser-based web skimmer that replaces deposit addresses, overrides the fetch API, and hijacks the clipboard. Later variants use the legitimate Tampermonkey extension with a user script for persistence without OS-level compromise. Talos identified 49 Bitcoin wallets, with 24 reused addresses receiving about 0.159 BTC (~$10,000) before mixing through more than 3,000 addresses.
BraZetsu Malware Turns Compromised Windows Hosts Into Criminal Marketplace Inventory
Group-IB details BraZetsu, a modular Python Windows malware that monetizes compromised-host access through the Infected Marketplace for initial access brokers.
Group-IB attributes BraZetsu to the Exilware threat actor, believed to be native Portuguese speakers targeting Iberian and Latin American e-commerce, financial, industrial, and law enforcement victims. The framework, first observed in early May 2026, uses generative AI for data triage and target prioritization, steals browser histories and digital certificates, and hunts Brazilian CNAB financial remittance files. Access to compromised hosts is sold on the Infected Marketplace from roughly $5.80, letting buyers remotely deploy secondary payloads over WebSocket-linked infrastructure. Some samples evaded detection on VirusTotal; delivery likely uses VBS loaders from a domain also used to distribute the Ousaban banking trojan.
Understanding Angler Exploit Kit
Unit 42 explains exploit kit fundamentals, describing how landing pages profile victims, deliver exploits, and install malware payloads on Windows hosts.
Unit 42 published a primer on exploit kit fundamentals, defining vulnerabilities, exploits, malware payloads, actors, and campaigns in EK-based attacks. It explains the infection chain: a landing page profiles the victim's Windows system for vulnerable applications such as Flash Player, Java, Silverlight, and Internet Explorer, then a matching exploit executes a downloader or final payload, often delivered encrypted with XOR or RC4. The post also describes the EK-as-a-Service business model, in which leading EKs are rented for a few thousand dollars per month while buyers supply campaign infrastructure.