A financially motivated operator ran three open-source AI agent harnesses (Strix, Cairn and Hermes) to break into at least 27 companies and take more than 600,000 unexpired payment card records, according to Gambit Security. In an interim report published on 22 September 2026, Gambit's director of threat intelligence, Eyal Sela, said the victims include a Fortune 500 hospitality company, a major US airline, a large private US industrial supplies distributor and a US online fashion retailer. Gambit rebuilt the campaign after it recovered the attacker's staging server. The operator's own cost review put the average completed scan at $25.46. The activity goes back to July 2026, and Gambit described it as still running at the time of disclosure. None of the named victims has made a public statement, and no regulator filing or CERT advisory has been published. Every figure below comes from Gambit's research as reported by the outlets and analysts cited. TNW notes that it has not independently verified the findings.
What Happened
Gambit says it reconstructed the operation from three kinds of evidence: material on the attacker's staging server (exfiltrated data and tooling), compromises it verified on live sites, and the operator's own logs. According to Gambit's report, The Register and Hackread, the operator launched 105 attack projects between 10 and 15 September alone and compromised at least 27 companies "to varying degrees." The agents worked through as many as "tens" of companies a day.
"Where access was achieved, it usually took less than a day, and in many cases just a few hours," Sela wrote.
The human operator had very little to do. Gambit counted 1,951 prompts across 260 sessions, which works out to a few prompts per target. Tech Times and Yahoo report that the prompts were short instructions written in Chinese. The Register describes the operator as Chinese-speaking. Gambit has not attributed the activity to any named group.
How far the campaign reached depends on which figure you use. Gambit's confirmed count is at least 27 companies in the six-day window from 10 to 15 September. Its report also says the operator targeted "hundreds of online retailers" and has affected "at least tens of other companies since July." Several secondary outlets (the Cloud Security Alliance, Tech Times and Yahoo Tech) use a figure of "100+" compromised sites or retailers. That number appears to come from Gambit's skimmer findings (see below), not from a confirmed count of breached companies. Read "27" as the confirmed minimum for one week and the larger figures as the wider footprint of the campaign.
What Was Taken
- Payment card data: Gambit's report says it can account for at least 600,000 unexpired credit card records, and that they came from two companies. They did not come from all 27 victims. The CSA research note gives the same attribution. Yahoo News reports that 79% of the cards were US-issued. No other source in this set repeats that figure, so treat it as unconfirmed.
- Skimmer installations: accounts differ here. Gambit's own report says card-stealing skimmer scripts were installed on the websites of five companies. TNW reports that Gambit confirmed skimmers at 19 of the named victims and found skimmers on more than 100 other websites. Yahoo Tech refers to "100+ skimmer sites." We give Gambit's primary figure of five the most weight. The larger numbers may cover skimmers found more widely during the investigation.
- Broader access: Gambit says the operator gained "some level of access" to assets at the hospitality, airline, industrial distribution and fashion retail victims. It has not described what data, if any, was taken from those companies.
- Destructive side effects: Gambit says the attacker's playbook contained data deletion and cleanup routines that "could disrupt the operations of a company," and that this "has indeed happened in some of the breaches." Sources describe the damage differently. The CSA says the agents destroyed database tables at one victim, and Tech Times says the agents accidentally destroyed a victim's database backups.
Why It Matters
Gambit and the CSA both present this as one of the most complete views so far of an autonomous AI attack pipeline, seen from the attacker's side instead of through victim forensics. Three things stand out for defenders:
- Very low cost. OpenRouter billing showed $7,005.71 spent in the four weeks to 25 August. The Register reports that the operator then kept going for three more weeks at roughly twice the daily volume of model calls. Gambit estimates the total at $12,000 to $18,000. A completed scan cost between $3.13 and $79.31, with a mean of $25.46 across 101 scans. At that price, attackers no longer need to be selective about targets.
- High speed with one operator. The CSA notes that 105 attack waves in a week from a single person is "a tempo and target count that would be very difficult for one person to achieve through manual exploitation." Most defenders set detection and response windows on the assumption of human-speed intrusions. Here, access usually came within hours.
- Damage nobody intended. Autonomous post-exploitation logic destroyed victim data. The CSA stresses that this collateral damage "need not have been deliberately intended or actively controlled by the operator." Incident responders should assume that an agent-driven intrusion may leave systems in an unpredictable state.
The tooling was freely available open-source software paired with commercial models bought through an API aggregator. Nothing about the stack was new or exclusive.
The Attack Technique
Gambit describes a three-layer pipeline:
- Strix (reconnaissance): an open-source AI penetration-testing tool that ran 146 times in "deep mode" against 138 hosts. Hackread and Tech Times report that this came to 633 hours of scanner time within about 195 hours of elapsed time, which requires heavy parallelisation. Tech Times dates this activity to 23 to 31 August. Strix ran on Z.ai's GLM 5.2 and later on DeepSeek V4 Pro.
- Cairn (exploitation): an autonomous penetration-testing engine. It was given a target domain and an objective, such as a shell or administrative access, and kept probing until it succeeded, timed out or was stopped. It ran on DeepSeek V4.1 Flash.
- Hermes (orchestration): the command layer, with persistent memory, scheduled jobs and a library of 121 skills, 78 of them offensive. Hermes also attacked targets directly and handled post-exploitation, running on Anthropic's Claude Opus 4.6. Yahoo News reports that the operator loaded a persona called "SOUL – Red Team Operator" and that one Hermes skill was built to strip the agent's own content-safety filters.
The operator reached all of the models through OpenRouter. Yahoo News reports that the operator moved to OpenRouter after Anthropic banned the account originally tied to their model access. No other source in this set confirms that.
The sources describe the exploited weaknesses only in general terms. The CSA calls them "common web application flaws," and none of the sources name specific CVEs. Once inside, the agents stole stored card data where it existed and planted JavaScript skimmers on checkout pages to capture cards as customers entered them.
What Organizations Should Do
- Monitor checkout page integrity. Use Content Security Policy with reporting, Subresource Integrity, and script-change monitoring on payment pages to catch injected skimmers. PCI DSS 4.0 requirements 6.4.3 and 11.6.1 already require this for card-handling sites.
- Stop storing card data you don't need. Two companies accounted for the full 600,000 records. Tokenise payments or hand them to a hosted processor so that a web-app compromise does not expose a card database.
- Shorten detection windows. Intrusions here took hours. Alert on high-volume automated probing, unexpected admin or shell access, and new outbound connections from web servers, and set up response playbooks that can act within hours instead of days.
- Test yourself with the same tools. Strix and similar open-source agents are available to defenders too. Run them against your own external attack surface before an attacker does, and fix the common web application flaws they find first.
- Protect backups from web-tier compromise. Autonomous cleanup routines destroyed victim data. Keep backups immutable and segmented so that compromised application credentials cannot reach them.
- Hunt retroactively. Gambit says the campaign began in July and was still active in late September. E-commerce operators, particularly in retail, hospitality and travel, should review web logs and checkout scripts back to July 2026 for signs of compromise.
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