Search: “session-token-theft”

Hackers are stealing Claude tokens from subscribers

Infostealer malware is stealing Claude login sessions, letting attackers mint OAuth tokens and burn subscribers' paid usage largely undetected.

Anthropic confirmed a bad actor used common infostealer malware to steal Claude login sessions from users' computers and consume their paid usage. A UK consultant saw idle token usage climb, and Anthropic suspended his account, invalidated sessions and Claude Code tokens, and issued a £44.49 partial refund on his $200-per-month plan. Multiple other users on Reddit and GitHub reported similar theft; Anthropic signed out affected users and issued refunds, but still lacks itemized usage reporting to help users detect misuse.

TechCrunch · AI·Sep 8, 21:10 UTC · 7d agoAI safety & security in the wild1

Malicious Twitch Extension Exposes OAuth Tokens of 30,000 Chrome and Firefox Users

Malicious 'Twitch Enhanced Viewer | JeetBot' browser extension stole live OAuth session tokens from roughly 31,000 Chrome and Firefox users.

Socket.dev found the cross-store extension 'Twitch Enhanced Viewer | JeetBot' rerouted Twitch playlist requests through operator-controlled proxies, attaching the victim's account-level OAuth token as a URL parameter where it could be logged in cleartext. About 30,000 Chrome and 552 Firefox installs were exposed, with tokens forwarded for nearly every watched channel to infrastructure tied to a Russian commercial bot service. The stolen bearer token enables chat, whisper, account-setting access and channel-point spending without the password or 2FA.

Cyber Security News·updated Sep 14, 15:00 UTC · 2d ago·first Sep 14, 13:50 UTC · 2d agoMalware in the wild 2 sources

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·Sep 8, 08:33 UTC · 8d agoPhishing & fraud in the wild1

JSCeal Malware Can Bypass Google Authentication Using Stolen Session Cookies

Check Point details JSCeal, a V8-compiled JavaScript stealer that replays stolen cookies to bypass Google authentication, spread via crypto malvertising.

Check Point Research's new report analyzes JSCeal, a compiled V8 JavaScript malware obfuscated with javascript-obfuscator using RC4-protected strings, control-flow flattening, and proxy functions. Delivered through fake TradingView installers on malvertising sites overlapping the WEEVILPROXY/MeadowLocust and SourTrade campaigns, it harvests cookies, passwords and OAuth tokens from Chromium browsers, records keystrokes and screenshots, and can replay stolen Google session cookies to bypass authentication. It also installs a local proxy with service-specific handlers for Binance, Bybit, and Ledger to intercept and modify cryptocurrency-related traffic.

The Hacker News·Sep 7, 07:53 UTC · 9d agoMalware in the wild1

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.

GBHackers·Sep 9, 06:22 UTC · 7d agoPhishing & fraud in the wild

Three Ukrainians to face charges for alleged hack of 610,000 Roblox accounts

Ukrainian prosecutors charged three men for stealing session tokens from over 610,000 Roblox accounts and selling them for an estimated $480,000.

Prosecutors in Ukraine's Lviv region said a 19-year-old organizer from Drohobych and two 22-year-old associates operated from May 2025 to April 2026, harvesting Roblox session tokens via infostealer malware disguised as game cheats and bonus software. They used software to validate stolen cookies and inventory virtual currency and rare items, then sold accounts via Russian platforms for as little as $0.80 each, advertising through Telegram channels and receiving crypto payments. All three are in custody facing charges of theft, money laundering, unauthorized computer interference, and illegal sale of restricted information, carrying up to 12 years in prison.

The Record·14:30 UTC · 4h agoPolicy & legal in the wild

From Infostealer Log to Marketplace Listing: A Technical Walkthrough of the Credential Theft Pipeline

Cyble walkthrough maps how infostealer logs move from endpoint infection through aggregation and enrichment to dark web credential marketplace sales.

Cyble breaks the credential theft pipeline into stages: infostealer execution harvesting browser credential stores, cookies, session tokens, crypto wallets, and FTP configurations; aggregation of stealer logs via C2 panels into bundled archives; parsing and enrichment against previously leaked datasets; and final listing on dark web marketplaces. Enrichment adds employer and role context that raises prices and enables credential stuffing across reused passwords. The report advises SOC teams to monitor stealer logs and marketplace chatter early rather than waiting for breach alerts.

Cyble·Sep 10, 10:45 UTC · 6d agoMalware1

Anthropic Users Hit by Infostealer Attacks, Session Thefts

A threat actor used multiple infostealers to harvest session data and hijack Claude accounts belonging to an unknown number of users.

Dark Reading reports that a threat actor deployed a variety of infostealer families to collect session information, which was then used to access Claude accounts belonging to an unknown number of users. Anthropic has not disclosed the scale of the compromise. The incident underscores session token theft via infostealer logs as an effective route into AI platform accounts.

Dark Reading·Aug 31, 21:08 UTC · 15d agoMalware in the wild

Infostealers are hijacking Claude accounts at users’ expense

Malwarebytes reports infostealers are stealing Claude session cookies to hijack Anthropic accounts and consume victims' usage at their expense.

Anthropic warned that infostealer malware operators are harvesting Claude session cookies from infected machines. Attackers replay the stolen cookies to take over users' accounts and consume their usage quotas, affecting the victims' own access. The activity involves observed account hijacking rather than a flaw in Claude itself.

Malwarebytes Labs·Sep 1, 10:08 UTC · 15d agoMalware in the wild

CVE-2026-37171: SuperTokens Core cross-tenant session isolation bypass (6.0.0-11.4.0)

CVE-2026-37171: SuperTokens Core 6.0.0-11.4.0 lacks tenant separation in session operations, enabling cross-tenant access.

CVE-2026-37171 (CWE-863, Incorrect Authorization) affects SuperTokens Core, the self-hosted authentication server by SuperTokens Inc., versions 6.0.0 through 11.4.0. The Core lacks tenant separation in session operations, permitting cross-tenant authorization bypass. The CVE is published, with advisory entries NVD and GitHub GHSA-j7vw-hh5c-2w6x; the disclosure does not mention any observed exploitation.

oss-security·Sep 9, 14:35 UTC · 7d agoVulnerabilityCVE-2026-371711

ClickFix moves into the browser: Cryptocurrency theft with Google-hosted C2

Talos tracks a crypto-theft campaign abusing the Google Visualization API for C2, using browser-based ClickFix lures to inject web-skimmer JavaScript.

Criminal actors convinced targets to paste JavaScript into Chrome's address bar or install it in the Tampermonkey extension, injecting a web skimmer into sessions on two cryptocurrency trading websites; Tampermonkey also provides persistence. Since March 2026 the campaign retrieved obfuscated scripts via the Google Visualization API from public Google Sheets documents, hooking the fetch API and replacing cryptocurrency deposit addresses in responses and the clipboard. Lures pose as leaked reports of a nonexistent API flaw at cryptocurrency swap services and spread via Telegram, DarkForums, and paste sites since early October 2025. Talos warns the legitimate-service-abuse techniques could enable wider supply-chain attacks on e-commerce and customer-facing systems.

Cisco Talos·Sep 8, 10:00 UTC · 8d agoPhishing & fraud in the wild

Stealing AI Reasoning Traces

Researchers demonstrate a decryption jailbreak that extracts encrypted reasoning traces from Anthropic, OpenAI, and Google LLM APIs via weaker sibling models.

The paper exploits the fact that encrypted chain-of-thought blocks returned by LLM providers are interchangeable across sessions, users, and models within a provider's ecosystem. Injecting an encrypted trace into a weaker, less-safeguarded model from the same provider forces it to output the trace in plaintext, bypassing anti-distillation mechanisms. Decoding 315,320 reasoning blocks scraped from public repositories recovered 367 PII artifacts and 182 credentials, showing large-scale private data leakage. The flaw also enables hidden hazardous information disclosure and invisible prompt injections embedded in encrypted blocks; mitigations were proposed after responsible disclosure.

Schneier on Security·Sep 8, 10:20 UTC · 8d agoAI safety & security

Chrome adopts what may be the best protection yet against account takeovers

Chrome adopts device-bound session credentials that tie login sessions to a specific device, defending against cookie-theft account takeover attacks.

Chrome is adopting device-bound session credentials, which bind authenticated sessions to the physical device rather than to transferable cookies. The mechanism targets a common account takeover technique in which attackers steal session cookies and replay them on other machines. Ars Technica characterizes it as possibly the strongest protection yet against this class of takeover, which has become increasingly common.

Ars Technica · Security·Aug 11, 20:59 UTC · Aug 11, 2026Tools

Hackers Target Claude, Cursor and Codex AI Agents to Steal Tokens and Prompt Histories

Gen Digital found infostealers like Amatera and Remus stealing AI coding agent tokens, prompt histories, and MCP configs from infected Windows and macOS machines.

Gen Digital analysts observed Amatera and Remus detections among tens of thousands of protected Windows users over three months, with Amatera targeting Cline and Continue data and Remus targeting Claude, Cursor, and OpenCode. CallbackBeaver added Cursor and Claude to its collection scope with more than 5,000 samples in 30 days, while macOS-focused Djinn Stealer has been associated with Claude, Codex, Gemini, Cline, OpenCode, and Kilo. The stealers harvest access and refresh tokens, prompt histories, and MCP configuration files that can expose source control, ticketing, databases, cloud resources, and sensitive project context for follow-on fraud. Many stealers add targets via remotely managed rules, meaning this is an adaptation of existing infostealers rather than a new vulnerability in the AI tools themselves.

Cyber Security News·Sep 9, 11:41 UTC · 7d agoMalware in the wild2

Mapping out your unknown: A threat hunter’s guide to GitHub

Datadog Security Labs publishes a threat-hunting guide with audit-log queries to detect GitHub token theft, device code phishing, and source code exfiltration.

Datadog's threat-hunting guide covers GitHub audit log queries for detecting compromised accounts, stolen personal access tokens, and malicious OAuth app authorizations. Attackers typically obtain credentials through phishing, credential stuffing, leaked secrets, or device code phishing, then map private repositories, exfiltrate source code, and pivot into connected cloud and CI/CD environments. The guide maps detections to MITRE techniques like T1078 and T1528 and documents GitHub logging quirks affecting attribution, token metadata, and visibility fields.

Datadog Security Labs·00:00 UTC · 18h agoResearch 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·Sep 2, 13:00 UTC · 14d agoPhishing & fraud in the wild1

The modern attack chain: Rethinking Google Workspace security in the age of AI

Analysis of Vercel and Composio breaches shows stolen OAuth tokens, not phishing email, now open Google Workspace attacks — a path authorized AI agents follow.

The author analyzes the Vercel and Composio breaches as the same OAuth-first attack chain run twice: a stolen OAuth token, obtained via a compromised supplier, becomes the entry point rather than email. These tokens survive password resets, are hard to observe, and let attackers read Gmail and Drive data, take over accounts, and pivot laterally using stored credentials and password-reset magic links. The piece warns that authorized AI agents with overbroad OAuth grants can unintentionally traverse the same path — accessing inboxes, reading sensitive content, and exfiltrating data downstream — without any malicious actor or compromised credential.

Help Net Security·05:00 UTC · 13h agoResearch in the wild

GhostCode Abuses Microsoft Entra Device Enrollment to Maintain Access After Token Revocation

eSentire exposes GhostCode, a device-code phishing kit that abuses Microsoft Entra device enrollment to persist even after stolen tokens are revoked.

eSentire's Threat Response Unit observed GhostCode campaigns in late August 2026, using BEC-style social engineering that impersonated procurement staff, including BJ's Wholesale Club, via Salesforce contact forms. Victims received password-protected HTML lures disguised as a FlipBook document portal, with junk-data padding, HTML comment injection, and AES-256-GCM encrypted redirects gated by anti-bot checks. The kit exploits the OAuth 2.0 device authorization grant, prompting victims to approve real Microsoft device-code sign-ins with MFA. Within 78 seconds of approval, attackers registered three Entra devices and obtained a Primary Refresh Token, so rogue device registrations persist even after session token revocation.

GBHackers·13:41 UTC · 4h agoPhishing & fraud in the wild

Session Attestation for Unmodified TLS Services in Confidential Virtual Machines

SessionLatch adds session attestation to unmodified TLS services in confidential VMs, cutting short-upload latency 63.1% versus TNG on Hygon CSV.

SessionLatch provides session attestation for confidential virtual machines without modifying applications, TLS implementations, or certificates. It relies on trusted observation of the server's locally generated ephemeral public key combined with standard TLS key confirmation, moving attestation integration to the operating system via a temporary latch that overlaps evidence exchange with the TLS handshake. Implemented with Linux and Windows integrations and evaluated on real Hygon CSV attestation, it reduces short-upload mean latency by 63.1%/23.0% relative to TNG in interleaved Linux/Windows experiments, while preserving enterprise service authentication and the native TLS data path, and supports mutual attestation.

arXiv cs.CR·Sep 9, 03:36 UTC · 7d agoResearch

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·Aug 31, 09:17 UTC · 16d agoMalware in the wild

'NovaCookies' Kit Steals Microsoft 365 Sessions for $320 a Month

New NovaCookies adversary-in-the-middle phishing kit lets low-skill actors steal Microsoft 365 session cookies for $320 per month.

Dark Reading reports on NovaCookies, an adversary-in-the-middle (AitM) phishing service sold for roughly $320 per month. The kit lowers the barrier to entry for attackers to run credential-harvesting attacks against Microsoft 365. It goes beyond credentials by stealing active session cookies, enabling account takeover without triggering MFA.

Dark Reading·Aug 26, 11:33 UTC · 21d agoPhishing & fraud

Credential Theft: How Attackers Steal & Use Stolen Credentials

Huntress explains how attackers steal credentials through phishing, AitM, infostealers, and dumping, then use them for lateral movement, BEC, and ransomware.

Huntress published an educational overview of credential theft, citing that roughly 70% of confirmed data breaches begin with stolen credentials. It details acquisition methods including phishing, adversary-in-the-middle attacks that capture MFA session tokens, infostealers (nearly a quarter of threats Huntress observed in 2025), Mimikatz-based credential dumping, credential stuffing, and password spraying. The piece then covers post-theft actions such as lateral movement, privilege escalation, account takeover, business email compromise, and ransomware, and closes with behavioral detection guidance and layered prevention strategies.

Huntress·Sep 10, 16:00 UTC · 6d agoResearch

ClickFix Moves into the Browser to Steal Cryptocurrency

Cisco Talos details a ClickFix campaign injecting browser JavaScript via Google Sheets to skim crypto deposits, stealing at least ~0.159 BTC since October 2025

Cisco Talos reported a months-long ClickFix campaign that shifted from OS command execution to injecting JavaScript through Chrome's address bar or the Tampermonkey extension into sessions on two cryptocurrency trading sites. Since March 2026 the operators fetch obfuscated payloads via the Google Visualization API from public Google Sheets, replacing displayed deposit addresses and amounts and overriding the fetch API, and the campaign survived two disruption attempts. Talos observed 49 Bitcoin addresses with 24 receiving at least 0.159 BTC (~$10,000) by early August, with proceeds routed through roughly 30 wallets and more than 3,000 addresses in apparent mixing. Lures posed as leaked vulnerability reports describing non-existent API flaws at crypto swap services, promising payouts up to 38% higher.

Infosecurity Magazine·Sep 9, 13:45 UTC · 7d agoPhishing & fraud in the wild

Attacker stole a METR API key, used $600K worth of credits, and no one noticed for weeks

Attackers stole a METR API key via an exposed agent-run EC2 instance and consumed about $600,000 in public model credits over three weeks.

AI evaluation nonprofit METR disclosed two incidents. In March 2026, a fail-open bug in a vibe-coded app disabled authentication on a publicly accessible EC2 instance; an attacker prompted the running agent to reveal a model provider API key, added an SSH key for persistence, and consumed roughly $600,000 in free public-model credits over three weeks without being noticed. In May 2026, attackers probed METR's public infrastructure using agents, automated vulnerability discovery, credential stuffing, OAuth token attempts, and phishing; a separately exposed read-only SQL mechanism found by a bug bounty hunter risked leaking unpublished evaluation data, but no access to non-public data was confirmed.

The Register · Security·Sep 1, 20:45 UTC · 14d agoData breach in the wild1

Webinar: How malicious OAuth apps can lead to Google Workspace breaches

BleepingComputer webinar will dissect two Google Workspace breaches caused by malicious OAuth apps and social engineering, hosted September 23 with Material Security.

On September 23, 2026, BleepingComputer will host a webinar with Material Security examining two real attacks that used malicious OAuth applications and social engineering to breach Google Workspace environments. Rather than stealing credentials, attackers persuaded users to authorize malicious apps, gaining access to data through the granted permissions. The session covers first-hour response decisions and which security controls provide the greatest value for fast-growing organizations.

BleepingComputer·Sep 14, 12:15 UTC · 2d agoPhishing & fraud

Doubloon Dredger Abuses Notion to Harvest Authentication Tokens

Doubloon Dredger malware abuses Notion and malicious PDFs to steal Microsoft authentication tokens from victims.

Doubloon Dredger is a malware campaign that abuses Notion and malicious PDF files to harvest Microsoft authentication tokens. Using a legitimate collaboration service likely helps the operation blend into trusted SaaS traffic and evade detection. Stolen Microsoft authentication tokens can enable account access without knowing user passwords.

Infosecurity Magazine·Aug 24, 13:00 UTC · 23d agoMalware in the wild1

Anthropic cracks down on hijacked user accounts mining AI tokens

Commodity infostealer malware hijacked Anthropic user accounts, letting criminals mine AI tokens on victims' paid usage; Anthropic cracked down on affected accounts.

The Register reports that Anthropic is cracking down on user accounts hijacked through commodity malware that steals authenticated browser sessions. With the stolen sessions, thieves ran AI workloads to mine tokens, freeloading on victims' paid usage allowances. The campaign illustrates how infostealer operators now monetize AI platform credentials and sessions, not just financial accounts.

The Register · Security·Aug 31, 16:03 UTC · 16d agoMalware in the wild

Hackers Abuse Google Sheets to Hijack Crypto Wallet Addresses in ClickFix Attacks

Cisco Talos details a crypto-theft ClickFix campaign abusing Google Sheets to swap wallet addresses, with about $10,000 in observed Bitcoin losses.

Cisco Talos tracks a ClickFix-style campaign that tricks cryptocurrency traders into pasting JavaScript into Chrome's address bar or a Tampermonkey extension, promising fake bonuses on SwapZone and SimpleSwap. The loader pulls obfuscated JavaScript from cells in a public Google Sheet via the Visualization API, then behaves like a web skimmer, rewriting deposit addresses on screen, in web responses, and in the clipboard. Researchers counted 49 attacker-controlled Bitcoin addresses, with 24 receiving a combined 0.159 BTC, roughly $10,000, by early August 2026. A Tampermonkey variant re-injects the payload on every return visit, giving the attackers persistence despite takedown efforts.

Cyber Security News·Sep 9, 10:57 UTC · 7d agoPhishing & fraud in the wild

Violent Physical Crypto Thefts Surge to $30m in Losses

Infosecurity Magazine·Aug 6, 12:00 UTC · Aug 6, 2026Data breach

Hackers Pose as Domain Controllers to Steal Active Directory Password Hashes

Attackers abuse Active Directory replication (DCSync) via the DRSUAPI protocol to steal password hashes and forge Golden Tickets for persistent domain compromise.

Security reporting citing Trellix details how threat actors impersonate domain controllers to request replication data and obtain NTLM password hashes without dumping LSASS on the domain controller. With Domain Admin or replication rights, attackers can steal the KRBTGT hash and forge long-lived Golden Tickets that survive password resets. Defenders should monitor DRSUAPI requests from non-DC systems, restrict replication permissions, and enforce MFA and tiered administrative access.

Cyber Security News·updated Sep 10, 12:00 UTC · 6d ago·first Sep 10, 11:29 UTC · 6d agoResearch 2 sources3· 1 read