Retail giant Target open sources Merry Maker e-skimmer detection tool

Retail giant Target announced the release in open-source of an internal tool, dubbed Merry Maker, designed to detect e-skimming attacks.

Merry Maker is a tool designed by Target security developers Eric Brandel and Caleb Walch (@ebrandel and @cawalch) to detect the presence of e-skimmer on e-store. The name comes from the tool’s ability to help keep the holiday shopping season – and all shopping occasions – safer and merrier.

The tool scans the payment page code for malicious pieces of software and analyzes saved network traffic for any potential compromise.

Merry Maker also works by preserving a baseline of existing pages by saving the code being served by a website along with the network traffic generated by test transactions

“Merry Maker continually simulates online browsing and completes test transactions to scan for the presence of malicious code. It acts like a guest on Target.com by completing several typical activities, including online purchases. While doing so, the tool gathers and analyzes a variety of information, including network requests, JavaScript files, and browser activity to look for any type of unwanted activity. Merry Maker was built to execute on all of this at scale.” reads the description of the project. “Merry Maker’s purchases are flagged as test orders internally so that they don’t get processed, but otherwise, everything happens behind the scenes just as it normally would during check out. If any possible malicious activity is detected, Merry Maker triggers an alert to Target’s 24/7 Cybersecurity Incident Response Team to prompt an investigation.”

Target is actively using Merry Maker since 2018, the tool has completed over one million website scans.

Target has open sourced the Merry Maker framework along with several detection rules that could be used by cybersecurity teams to set up and customize their defense.

“Today we’ve open sourced the Merry Maker framework along with several detection rules in the hopes that this information helps other cybersecurity teams stand up their own customized defense. Digital security is a team sport – a threat to one is a threat to all – and entities need to work together to create safe online environments for consumers.” concludes Target. “We’re proud to be a leading sharer and collaborator across the retail industry and we hope Merry Maker helps others protect against digital skimming attacks.”

Target pointed out that security experts can create their own detections rules via Typescript.

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Pierluigi Paganini

(SecurityAffairs – hacking,  Merry Maker)

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