Legacy Stripe API Exploited to Validate Stolen Payment Cards in Web Skimmer Campaign
Apr 03, 2025
Cybersecurity / Threat Intelligence
Threat hunters are warning of a sophisticated web skimmer campaign that leverages a legacy application programming interface (API) from payment processor Stripe to validate stolen payment information prior to exfiltration. "This tactic ensures that only valid card data is sent to the attackers, making the operation more efficient and potentially harder to detect," Jscrambler researchers Pedro Fortuna, David Alves, and Pedro Marrucho said in a report. As many as 49 merchants are estimated to have been affected by the campaign to date. Fifteen of the compromised sites have taken action to remove the malicious script injections. The activity is assessed to be ongoing since at least August 20, 2024. Details of the campaign were first flagged by security firm Source Defense towards the end of February 2025, detailing the web skimmer's use of the " api.stripe[.]com/v1/sources " API, which allows applications to accept various payment methods. The endpoint has...