Thousands of Magento-powered online stores have been hacked over the past few days as part of a skimming campaign that has been described as the “largest ever.”
The attack is being monitored by Sansec, a Netherlands-based cybersecurity company that specializes in solutions designed to counter digital skimming. Sansec on Monday reported seeing nearly 2,000 Magento stores that have been compromised as part of this campaign since Friday — over 1,000 stores were hacked on Saturday, more than 600 on Sunday, and over 200 so far on Monday.
A majority of the impacted sites were powered by Magento 1, but some were running Magento 2.
Sansec says this is the largest automated campaign it has seen to date since 2015, when it started monitoring the threat landscape.
“The previous record was 962 hacked stores in a single day in July last year,” the company explained in a blog post. “The massive scope of this weekend’s incident illustrates increased sophistication and profitability of web skimming. Criminals have been increasingly automating their hacking operations to run web skimming schemes on as many stores as possible.”
As part of this campaign, which involves what researchers have described as a typical Magecart-style attack, the hackers have been planting a payment card skimmer on targeted websites. The malware is designed to steal information entered by users on the checkout page of a compromised store, exfiltrating it to a server hosted in Russia.
Sansec believes tens of thousands of people likely had their personal and financial information stolen from the impacted websites over the weekend.
While the attack is still being investigated, the cybersecurity firm believes the cybercriminals might be using a new Magento exploit that was offered a few weeks ago on a hacking forum for $5,000. The seller, a Russian speaker, claimed the exploit allowed remote code execution and said he was only selling 10 copies.
The exploit allegedly targeted Magento 1 websites. Magento 1 has reached end of life and Adobe is no longer releasing patches for it, but there are still an estimated 95,000 websites powered by this version, Sansec said.
Related: Six Critical Vulnerabilities Patched in Magento
Related: Hackers Accessed Magento Marketplace User Data
Related: Magento 2.3.4 Patches Critical Code Execution Vulnerabilities