Visa Warns of JavaScript Skimmer Baka that Steals Payment Card Data

Visa alerts of a brand-new e-commerce skimmer dubbed Baka that loads malware dynamically to prevent static malware scanners and special file encryption to obfuscate the harmful code for every single customer.

Visa Payment Fraud Disruption (PFD) observed this skimmer across a number of merchant sites across multiple international regions.

Baka JavaScript Skimmer

Visa asks merchants to routinely scan and test eCommerce websites for vulnerabilities or malware, ensure shopping carts, other services, and all software are upgraded or patched.

PFD observed that seven C2 servers hosting the Baka skimming kit, the skimmer includes functions that prevail for an e-commerce skimmer such as information exfiltration from the target fields.

The skimmer version is developed to eliminate itself from memory when it spots any possibility of vibrant analysis with developer tools, this method is to avoid detection and analysis.

The Baka loader script works dynamically by including a script tag to the present page that loads the remote JavaScript file.

Based on its sophisticated style Baka believed to be created by an experienced developer, the most engaging features of the skimmer is its unique loader and obfuscation method.

Once the skimmer gets executed it captures the data from the checkout type, it keeps scanning the fields for each 100 milliseconds. If it fetches the data then it sets a flag called this.load showing the skimmer effectively exfiltrated information.

When the user reaches the checkout page the loader carries out the harmful skimming code, then it decrypts the skimming code and executes it in memory. The skimming code performs dynamically so it never ever present on the merchants server or saved to the clients computer system.

The last process of the skimmer is cleaning up if the data is exfiltrated effectively it removes the whole skimming code from memory to prevent detection.

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