Attacks that compromise websites with scripts that steal payment card data from checkout pages have increased to hundreds of thousands of attempts in little over a month.

The most publicized incidents resulting from these attacks are from cybercriminal campaigns known as Magecart, with one group apparently being responsible for compromising the websites of Ticketmaster, British Airways, Feedify, and Newegg.

Magecart campaigns consist of breaching websites and injecting a malicious script that loads on payment pages to collect the card details provided by users at checkout. The data is packaged and sent to a domain controlled by the attacker. This form of theft is also known as formjacking, payment card scraping or web-based skimming.

Symantec noticed a rise of this type of attack recently, recording 248,000 attempts since August 13, with most of them (36%) occurring September 13 through 20.

"If we compare the week of September 13 to 20 to the same week in August, the number of instances of formjacking blocked by Symantec more than doubled, jumping from just over 41,000 to almost 88,500—a percentage increase of 117 percent," Symantec informs.

Symantec is not the only one doing something against Magecart activity. Earlier today, security researcher Kevin Beaumont tweeted that the number of domains and scripts associated with Magecart campaigns reached more than 1,000.

Yesterday, the researcher had just 78 indicators of compromise (IoC), showing that the campaign is in full swing.

His efforts are not singular in this endeavor, as cybersecurity company RiskIQ has been sinkholing domains in the Magecart infrastructure since last week.

Yonathan Klijnsma, Threat Researcher Lead for RiskIQ, says that they're also alerting affected parties of the compromise.

Magecart activity has been tracked since 2015 by at least one security expert, Willem de Groot. He created the MageReport malware scanning website where one can check if their Magento-based webshop is vulnerable to known security issues.

de Groot's scanner now includes Magecart IoCs collected by Kevin Beaumont, allowing more websites to check their code for tracks pointing to a Magecart campaign.