Infostealer Logs Expose Replayable AI Session Tokens and API Keys Enabling MFA Bypass

Infostealer Logs Expose Replayable AI Session Tokens and API (TL-2026-2416), also tracked as AI Session Token Campaign, is a high-severity tracked intrusion set, first published 2026-09-09. It has no confirmed attribution, affects Google Gemini API, maps to 14 MITRE ATT&CK techniques (T1005, T1027, T1053), and is covered by 9 detection rules and 17 indicators of compromise.

Key facts for TL-2026-2416

Threat ID
TL-2026-2416
Also known as
AI Session Token Campaign, Token Jacking Campaign, Operation Bizarre Bazaar
Severity
HIGH
Status
ACTIVE
Category
THREAT_INTEL
First published
2026-09-09
Last reviewed
2026-09-09
Attribution confidence
LOW
Motivation
FINANCIAL
Target sectors
technology, cloudcomputing, artificialintelligence, saas, finance, government administration, health
Target regions
Worldwide
Detection rules
9
Indicators of compromise
17

Malware and tooling in Infostealer Logs Expose Replayable AI Session Tokens and API

Malware and tooling: CASTLELOADER, Lumma Stealer - S1213, LummaC2 / Lumma Stealer, RedLine, Stealc, Vidar, AI LLM endpoints (LLM), Camoufox, NORDSTREAM, QUIETVAULT

Okta analysis of a 7 GB infostealer dump published to Telegram on August 2, 2026 spanning 5,871 infected machines across 162 countries found 44,791 unique JWTs including 555 likely tied to AI service authentication, 24 still-valid API keys for Google Gemini, OpenAI, Groq, and OpenRouter, and plaintext PII in 17.7% of tokens. Stolen sessions replayed against Google, Anthropic, OpenAI, and other LLM platforms bypass username/password and MFA, enabling LLMjacking, resource theft, and extortion. Mandiant documented one incident where an exposed GitHub PAT led to unauthorized AI infrastructure deployment in a victim's cloud environment via the UNC6426 threat cluster abusing an npm supply chain attack.

How Infostealer Logs Expose Replayable AI Session Tokens and API works

In early August 2026, a 7 GB archive of infostealer logs was published to a Telegram channel, exposing data from 5,871 infected machines across 162 countries. Okta's threat intelligence team analyzed the dump and identified 44,791 unique JSON Web Tokens (JWTs), of which 555 were likely tied to AI service authentication, and 2,937 JWE structures (encrypted JWTs set by OpenAI via NextAuth.js). Notably, 1,843 JWTs and JWEs remained unexpired on the release date, and 17.7% of all tokens contained plaintext personally identifiable information (PII) including names, phone numbers, and email addresses that never expire or disappear.

Using automated scanning tools including TruffleHog, Okta validated 24 still-active API keys for AI services across Google Gemini, OpenAI, Groq, and OpenRouter. These API keys enable LLMjacking — unauthorized use of cloud-hosted LLM inference capacity — where attackers route requests through subscription accounts they have not paid for, running up compute bills charged to the original account holder. Financial exposure can reach $46,000 per day per victim for AWS Bedrock deployments, and over $100,000 per day for frontier model access. The attack chain exploits a fundamental session security gap: a valid session token issued after successful MFA is stored in the browser and can be exfiltrated by infostealer malware, then replayed from a different device with no additional authentication.

Two infostealer families were identified as primary harvesters: Lumma Stealer (LummaC2) and Vidar. Both employ advanced browser data extraction techniques, including defeating Google Chrome v127+ App-Bound Encryption (ABE) through process injection — Lumma uses QueueUserAPC() to inject into chrome.exe and call Chrome's IElevator COM interface from within the trusted process, while Vidar uses NtCreateProcessEx to fork the browser's memory and APC injection to call CryptUnprotectMemory. These techniques allow extraction of HttpOnly and Secure-flagged cookies with full session validity. Delivery mechanisms include phishing campaigns, malvertising (fake Notepad++ and Chrome update ads), ClickFix fake CAPTCHA lures that execute PowerShell commands, EtherHiding via Binance Smart Chain smart contracts for malware hosting, and cracked software downloads.

The stolen credentials feed an established underground economy. Okta documented Telegram vendors selling discounted access to Claude, Cursor, ChatGPT, and Gemini with 24/7 support and money-back guarantees. A service called "Poison Claude" (poison-claude.bitsender[.]top) resells access to Anthropic models including Opus 4.8, Opus 4.7, and Sonnet 4.6 at 5-15% of official per-token pricing; a misconfigured API endpoint revealed 881 total and 872 active users. Ecomagent.in operates similarly with ~970 users and claims to support Opus 4.8/5, Fable 5, Sonnet 5, and GPT-5.6 on flat monthly subscriptions from $19/month. A broader operation, Operation Bizarre Bazaar, mapped 35,000 attack sessions between December 2025 and January 2026 through the silver.inc marketplace, which resold access to 30+ LLM providers at 40-60% discounts and was attributed to a threat actor using the alias "Hecker."

Google's Mandiant team documented the UNC6426 threat cluster, which exploited the downstream consequences of the August 2025 s1ngularity npm supply chain attack. A malicious npm package executed a QUIETVAULT credential-stealing postinstall script that harvested GitHub Personal Access Tokens, npm tokens, SSH keys, cloud provider credentials, and AI tool configuration files. QUIETVAULT notably detected locally installed AI CLI tools — Claude Code, Google Gemini CLI, and Amazon Q Developer — and invoked them with permission-bypass flags (--dangerously-skip-permissions, --yolo, --trust-all-tools --no-interactive) to recursively scan the filesystem for additional sensitive material. This is the first documented instance of AI CLI tool weaponization within a supply chain postinstall script. The stolen PAT was used with NORDSTREAM (an open-source CI/CD extraction tool) to enumerate workflows and trigger GitHub Actions, exploiting an AWS OIDC trust policy lacking a scoped sub condition to achieve full AWS administrator access in under 72 hours, ultimately stealing 2,349 distinct secrets from 1,079 compromised repositories.

The Flare 2026 State of Enterprise Infostealer Exposure report provides broader context: 2.05 million infostealer logs exposed enterprise identity credentials in 2025 alone, with ~1.17 million logs containing both credentials and live session cookies enabling immediate MFA bypass. Enterprise identity exposure rose from ~6% of infections in early 2024 to ~16% in early 2026. Microsoft Entra ID appeared in 79% of enterprise identity logs. Despite a 20% year-over-year decline in total infostealer infections, enterprise identity exposure continued rising, indicating a structural shift toward targeted high-value enterprise credential theft.

Defensive recommendations include deploying Google's Device Bound Session Credentials (DBSC) in Chrome 145+ (which cryptographically binds session tokens to a specific device using TPM/Secure Enclave), implementing phishing-resistant FIDO2/WebAuthn MFA, continuous access evaluation, short-lived OAuth tokens with automatic rotation, scoped API keys per service, IP allowlisting for AI API endpoints, and proactive monitoring of organizational domains against leaked-log corpora. Okta noted that even passkeys do not prevent a stolen session token or API key from being replayed.

MITRE ATT&CK techniques used in TL-2026-2416

Collection

T1005 Data from Local System

Defense Evasion

T1027 Obfuscated Files or Information; T1055 Process Injection

Persistence

T1053 Scheduled Task/Job

Execution

T1059 Command and Scripting Interpreter

Initial Access

T1195 Supply Chain Compromise; T1566 Phishing

Impact

T1496 Resource Hijacking

Credential Access

T1528 Steal Application Access Token; T1539 Steal Web Session Cookie; T1555 Credentials from Password Stores

Exfiltration

T1567 Exfiltration Over Web Service

Resource Development

T1583 Acquire Infrastructure; T1588 Obtain Capabilities

Affected products and versions in Infostealer Logs Expose Replayable AI Session Tokens and API

  • Google — Gemini API
  • OpenAI — ChatGPT / API
  • Anthropic — Claude (Web + API)
  • Microsoft — Azure OpenAI / Entra ID
  • Amazon — AWS Bedrock
  • Groq — LLM API
  • OpenRouter — LLM API Gateway

Remediation for Infostealer Logs Expose Replayable AI Session Tokens and API

Patches

  • Update all browsers to latest versions supporting App-Bound Encryption (Chrome 127+ with ABE)
  • Implement FIDO2/WebAuthn phishing-resistant MFA across all identity providers
  • Deploy Endpoint Detection and Response (EDR) with process injection detection rules

Immediate actions

  • Rotate all credentials and API keys on potentially compromised systems
  • Revoke all active session tokens for AI service accounts
  • Block known malicious domains (poison-claude.bitsender.top, api.claudeopus.shop, ecomagent.in, silver.inc) at perimeter
  • Enforce credential rotation for all AI service accounts and cloud provider access keys
  • Force logout of all active sessions across AI platforms

Workarounds

  • IP allowlisting for AI API endpoints where operationally feasible
  • Use managed/compliant-device policies for accessing sensitive AI service consoles
  • Split production and development API keys with separate rate limits and budgets
  • Implement usage quotas and budget alerts on all AI/LLM API subscriptions

Longer-term hardening

  • Deploy Google Device Bound Session Credentials (DBSC) in Chrome 145+ to cryptographically bind session tokens to devices
  • Implement continuous access evaluation (CAE) to force re-authentication on IP/device/risk signal changes
  • Enforce short-lived OAuth tokens with automatic rotation (maximum 1-hour expiry for API keys)
  • Deploy scope-limited, per-service API keys with resource-level IAM policies
  • Implement AI service usage anomaly detection with secondary authentication signals
  • Monitor organizational domains against leaked-infostealer-log corpora (Flare, HudsonRock, SpyCloud)

Timeline of Infostealer Logs Expose Replayable AI Session Tokens and API

  • s1ngularity npm supply chain attack launches; QUIETVAULT postinstall script harvests credentials from 1,079 repositories
  • Operation Bizarre Bazaar begins; attackers scanning for exposed Ollama, vLLM, and MCP endpoints
  • Flare 2026 stats report indicates 2.05 million infostealer logs with enterprise credentials in 2025 and 1.17 million with live session cookies enabling immediate MFA bypass
  • Sysdig and Pillar Security Research document Operation Bizarre Bazaar; 35,000 attack sessions captured, silver.inc marketplace unmasked
  • Law enforcement disruption of Lumma C2 domains; thousands of domains taken offline
  • Google DBSC becomes generally available in Chrome 145 on Windows, cryptographically binding session tokens to specific devices via TPM
  • 7 GB infostealer dump published to Telegram — 5,871 infected machines, 44,791 JWTs, 555 AI-service tokens, 24 still-valid API keys for Gemini, OpenAI, Groq, OpenRouter
  • Okta publishes 'Free Tokens for Sale: How Fake Signups Drive AI Fraud'; documents Poison Claude, Ecomagent.in, and the gray market AI access ecosystem
  • IT Pro reports on criminals selling discounted AI tokens; identifies the Poison Claude proxy model and user base of 872 active users
  • Anthropic warns users that infostealers (Vidar, LummaC2, StealC, Raccoon, RedLine, Arcid, M0S) are clawing session cookies to drain paid accounts
  • SecurBlink reports on infostealer malware hijacking Claude sessions; Unit 42 'Token Jacking' research documents traffickers reselling access at 87-93% below list price
  • Lunar Cyber publishes 'Token Haystack' analysis of parsing exposed tokens from stealer logs
  • The Hacker News publishes the exposure of replayable AI session tokens; threat ID TL-2026-2416 created

Sources cited for Infostealer Logs Expose Replayable AI Session Tokens and API

More in threat intel

Detection coverage for TL-2026-2416

As of 2026-09-09, Threadlinqs Intelligence publishes 9 detection rule(s) for TL-2026-2416 across Splunk SPL, Microsoft KQL and Sigma, covering 17 indicator(s) of compromise. The whole corpus is readable without an account; a free account unlocks full detection query text in Splunk SPL, Microsoft KQL and Sigma; paid tiers add raw indicator values, correlation and the MCP server. Threadlinqs MCP server · View plans.

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