Data Magecart, a Brazilian group of hackers, compromised the analytics script used by e-commerce platform Convertr, potentially revealing payment information provided by customers to dozens of Brazilian fashion brands. During the attack, which was detected by cybersecurity firm Sansec on October 24, 2026, malicious code was injected into Convertr's Plausible analytics tracker.
By modifying a JavaScript file loaded into Convertr's merchant checkouts, the attackers allowed the card skimmer to collect sensitive information during online purchases by modifying the JavaScript file. The data obtained was comprised of card numbers, expiration dates, CVV security codes, cardholder names, and Brazilian CPF taxpayer identification numbers.
The information was transmitted to a server controlled by the attacker at 1x0.is. Online shopping and checkout services are provided by Convertr to dozens of Brazilian fashion retailers. According to the platform, its merchants have processed more than R$2 billion in sales. Due to the fact that the affected analytics tracker was distributed throughout its merchant network, compromising one file created a potential supply chain risk that extends beyond one individual online store.
The malicious script was detected by Sansec after a clean version was captured earlier on October 24th. In October, the attackers modified the skimmer in order to target Convertr's payment API field names, making it more effective in capturing payment information. Researchers also reported that the compromised tracker continued to serve on October 26, despite efforts to notify Convertr.
As Sansec has been tracking the Brazilian Magecart group since July 2024, the incident represents a significant development in its activities. The group has previously targeted individual online stores using Magento, OpenCart and WooCommerce, mainly in Brazil. With the Convertr compromise, Sansec has shifted from infecting individual stores to compromising a service shared by multiple businesses, resulting in the first supply chain attack attributed to the group.
An unpatched installation of Plausible Community Edition, an open-source web analytics platform, is believed to have been the source of the attack. Versions 3.0.0 through 3.2.0 were affected by CVE-2026-8467, a critical vulnerability that could allow unauthenticated command execution through an exposed component of the /storybook component.
Convertr reported installing version 3.0 in 2025 and not updating it prior to the incident. On May 15, 2026, Plausible released version 3.2.1 which fixed the vulnerability. Since researchers were not able to access the platform’s server logs, Sansec has not confirmed that the vulnerability was exploited to gain access. Therefore, it remains unclear what specific method was used to compromise the analytics server. Furthermore, the group has consistently targeted Brazilian payment systems as a focus for their methods.
According to Sansec, its skimmers exhibit recurring characteristics, including the use of short-lived domains as recipients of stolen information, and endpoints containing Portuguese names related to card payments. Other variants have also been developed to attack payment services, including e.Rede, PagSeguro, Pagar.me and Mercado Pago.
Another version is reported to replace genuine PIX payment QR codes with malicious codes. Convertr confirmed on October 27 that Plausible had been updated with a patched version following the discovery of the malicious script. In addition to notifying affected merchants, payment providers, and relevant authorities, the company also verified that the tracker hosted on Convertr's analytics server was free of infection.
While it is important to remove malicious code, it does not necessarily eliminate all immediate risks for all shoppers. Sansec stated that browsers may retain cached copies of infected scripts for up to 24 hours following the server-side cleanup, potentially allowing the malicious code to remain active during that period.
Payments made by Brazilian customers through checkout addresses containing checkout.convertr from October 24 onward should be blocked and replaced by their banks. It is also recommended to monitor transactions for suspicious activity involving CPF identification numbers in order to identify suspicious activity.
A Sansec recommendation for organizations using Plausible Community Edition is to update the version to 3.2.1 or later and to review server access logs for requests to the exposed path of /storybook. Upon detecting evidence of exploitation, the affected server should be rebuilt, secrets rotated, tracker files checked against the official release, and a more thorough investigation conducted. The incident emphasizes the wider risks associated with shared web infrastructure.
Multiple businesses can be affected by compromised analytics scripts without the attacker having to breach each merchant individually. To reduce the risk of similar attacks, it is vital that software be updated, scripts loaded on payment pages are monitored, and unauthorized outbound connections are restricted.
This incident illustrates the dangers posed by compromised third-party scripts used on checkout pages. Preventing digital skimming attacks requires timely software updates, continuous script monitoring, and stronger protection of payment infrastructure.
