AI Agents Hacked Over 100 Online Stores for About $25 Each: The 30-Minute Checkout Check for Yours

What happened. On September 22 and 23, 2026, Gambit Security published an investigation into an ongoing campaign that used three open-source AI agent tools to attack online stores. One agent scanned sites for weak spots, one broke in, and one ran the operation and planted the skimmer. A human gave short instructions. The agents did the rest. Reported numbers: more than 600,000 payment card records stolen, skimmers found on well over 100 sites, 105 attack projects launched in six days from September 10 to 15, and an average cost of about $25 per target.

How the skimmers got in. The reports describe three routes: hijacking legitimate scripts already running on the store, changing the store's Google Tag Manager setup, and poisoning content the site loads from cloud storage. Reports also describe a tool built to wipe stolen card data from Magento store databases.

Why it matters to you. At $25 a target, attackers no longer need your store to be worth their time. Every store with a checkout page is in range. A skimmer is quiet: orders go through, customers pay, and you find out weeks later when your processor calls about fraud traced back to your site.

The 30-minute checkout check.

1. Find out where card numbers get typed. Place a test order and look at the payment step. If the card fields are hosted by your processor (Shopify checkout, a Stripe or PayPal hosted page or hosted fields), your exposure is smaller. If card numbers go into a form your own site or developer built, ask your developer this week about moving to hosted fields.
2. Lock Google Tag Manager. Open Google Tag Manager, go to Admin, then User Management. Remove anyone who no longer works with you, including past agencies and freelancers. Leave publish rights with one or two people. Make sure everyone left signs in with 2-step verification.
3. Lock the store admin. List every admin login on your store platform. Remove old staff and old vendors. Turn on 2-step verification for every account that remains.
4. Ask about patches. If your store is self-hosted (Magento, Adobe Commerce, WooCommerce), ask whoever maintains it for the date of the last security update to the platform and every plugin. Hosted platforms patch their own core, but apps and scripts you add are still yours to watch.
5. Take a script inventory. List every tag in Tag Manager and every app or plugin installed on the store. Then run the prompt below.

Paste this into your business AI workspace:

I run an online store on [platform]. Card payments are handled by [processor, and whether card entry is hosted by them or on my own page]. Here is every tag in my Google Tag Manager container and every app or plugin installed on my store: [paste the names and descriptions only]. For each one, tell me what it most likely does, whether it could run on my checkout or payment pages, and whether I should keep it, ask my developer about it, or remove it. List every item where you cannot tell what it does. Then write 5 questions I should ask my developer or platform support about checkout security this week. Do not guess about anything you cannot identify. Mark it unknown.

Keep it private. That prompt needs tag and app names only. Never paste customer orders, card data, or passwords into any AI tool.

One more thing. PCI DSS, the card industry's security standard, already asks merchants to keep an inventory of the scripts on payment pages. Ask your processor which requirements apply to your setup. It is usually a short answer.