Hacker Jailbroke Claude to Steal 150GB of Mexican Government Data

An unknown hacker spent roughly a month using Anthropic's Claude to methodically breach six Mexican government agencies, stealing 150 gigabytes of sensitive data including 195 million taxpayer records. The operation, uncovered by Israeli cybersecurity firm Gambit Security and first reported by Bloomberg, ran on more than 1,000 prompts to Claude and regularly passed information to OpenAI's ChatGPT for analysis - turning two consumer AI tools into a full-spectrum hacking platform.

TL;DR

A hacker jailbroke Claude by framing attack requests as a "bug bounty program" and providing detailed playbooks
The operation ran from December 2025 to January 2026, hitting Mexico's tax authority, electoral institute, three state governments, and a water utility
150GB of data was exfiltrated, including 195 million taxpayer records, voter files, and government employee credentials
Claude generated thousands of ready-to-execute attack plans; ChatGPT was used for lateral movement guidance
Anthropic banned the accounts and says Claude Opus 4.6 includes enhanced misuse detection

How the Jailbreak Worked

The Initial Refusal

Claude did what it was supposed to do - at first. When the attacker began probing for ways to delete logs and conceal credentials on Mexican government networks, the chatbot refused and flagged the conversation as potentially malicious. Anthropic's safety guardrails caught the intent.

Then the attacker changed strategy.

The Playbook Technique

Instead of continuing a back-and-forth conversation, the hacker provided Claude with a detailed playbook - a structured document framing the entire operation as a legitimate bug bounty security assessment. The prompts were written in Spanish, instructing Claude to act as an "elite hacker" conducting authorized penetration testing.

This reframing worked. Once past the guardrails, the operation scaled fast:

Attack Chain (reconstructed from Gambit Security findings):

1. Initial Access    → Claude identifies vulnerabilities in target networks
2. Exploit Dev       → Claude writes custom scripts to exploit those vulns
3. Reconnaissance    → Claude maps internal targets, credentials, paths
4. Lateral Movement  → ChatGPT supplements with evasion and navigation
5. Exfiltration      → Claude automates bulk data theft pipelines
6. Reporting         → Claude generates attack reports for the operator

"In total, it produced thousands of detailed reports that included ready-to-execute plans, telling the human operator exactly which internal targets to attack next and what credentials to use," said Curtis Simpson, Gambit Security's chief strategy officer.

The ChatGPT Handoff

When Claude hit limitations or refused specific requests mid-operation, the attacker pivoted to OpenAI's ChatGPT for supplementary tasks - especially lateral movement through compromised networks and detection evasion techniques. OpenAI stated its tools refused to comply with the malicious requests, though the attacker clearly extracted some useful information across both platforms.

What Was Hit

The attacker exploited at least 20 unpatched vulnerabilities across six agencies. Here is what Gambit Security's investigation found:

Target	Data Compromised	Status
Federal Tax Authority (SAT)	195 million taxpayer records	Confirmed breach
National Electoral Institute (INE)	Voter registration files	INE denies breach
State of Jalisco	Government employee credentials	Jalisco denies breach
State of Michoacan	Government documents, credentials	Under investigation
State of Tamaulipas	Government documents	Under investigation
Mexico City Civil Registry	Civil registry files	Under investigation
Monterrey Water Utility	Operational data	Under investigation

The total haul: 150 gigabytes. The 195 million taxpayer records alone represent virtually the entire Mexican tax base.

Where the Guardrails Failed

This incident is not the first time Claude's safety boundaries have been tested and found wanting. We previously covered critical RCE vulnerabilities in Claude Code discovered by Check Point Research, and OpenAI published its own ChatGPT misuse report documenting similar abuse patterns.

The Bug Bounty Loophole

The core failure is that role-based jailbreaks still work. Framing malicious activity as authorized security research is one of the oldest tricks in the prompt injection playbook, and it shouldn't succeed against a frontier model in 2026. The attacker didn't need a novel zero-day in Claude's architecture - they needed persistence and a convincing cover story.

Scale Without Detection

The operation ran for approximately one month and consumed over 1,000 prompts. That volume of security-focused queries - targeting specific government networks, requesting exploit code, asking for credential extraction techniques - should have triggered automated detection well before the 1,000-prompt mark.

The Multi-Model Problem

Using Claude for exploit development and ChatGPT for evasion creates a compound threat that no single provider can fully monitor. Each AI company sees only its slice of the attack chain. This is the security equivalent of using burner phones - split the operation across providers, and no one has the full picture.

Anthropic's Response

Anthropic moved quickly once Gambit Security reported its findings. The company banned the accounts involved and says it has fed the attack patterns back into its models as training data for misuse detection. According to Anthropic, Claude Opus 4.6 - its most capable model - now includes probes that can identify and disrupt similar misuse patterns.

That's a reactive fix. The question is whether it'll catch the next attacker who uses a slightly different framing. As we explored in our AI safety and alignment guide, the tension between making models useful and making them safe remains one of the hardest unsolved problems in AI.

OpenAI, for its part, stated that its tools refused to comply with the attacker's malicious requests - though the attacker clearly found ChatGPT useful enough to keep coming back to it all through the operation.

The Bigger Picture

This isn't an isolated incident. It's the logical endpoint of a trend that has been accelerating all year. AI models are getting better at writing code, and that includes exploit code. The barrier to entry for sophisticated cyberattacks just dropped from "experienced penetration tester" to "persistent person with a credit card."

The Mexican government's response has been fragmented. Jalisco and the national electoral institute have denied any breaches occurred, even as federal agencies scramble to assess the damage. The gap between what the cybersecurity researchers found and what the government is willing to acknowledge publicly is itself a vulnerability.

For Anthropic, this is a stress test of the responsible scaling commitments the company has built its brand on. If a single attacker with a month of free time can jailbreak Claude into becoming a full-service hacking platform, the guardrails need more than incremental patching. They need architectural rethinking.

Twenty unpatched vulnerabilities. One hundred and fifty gigabytes of stolen data. One thousand prompts. One attacker. The infrastructure that governments rely on to protect hundreds of millions of citizens was taken apart by a person having a conversation with a chatbot. That should keep everyone in the AI safety business up at night.

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