Hackers abuse Google Ads, Bing redirects to push Claude ClickFix attacks

Hackers are abusing legitimate Bing search-result redirects as click URLs in Google search ads to direct users to fake Claude installers that deliver ClickFix attacks.

The technique, dubbed "Adception" by security researchers at Push Security, appears designed to evade advertising security checks by using Bing's trusted domain as the ad destination, before redirecting victims through a compromised website to the malicious download page.

The attack also uses multiple layers of cloaking to prevent security scanners and visitors who access the malicious URLs directly from seeing the payload.

According to a report published by Push Security, the campaign was discovered after researchers detected a malicious Google ad targeting users searching for "claude mac."

Unlike typical malvertising campaigns that direct victims to attacker-controlled domains, the sponsored result displayed the legitimate bing.com domain, making the advertisement appear less suspicious.

When clicked, Push says the ad first passed through Google's advertising redirect before reaching Bing's bing.com/ck/a click-tracking endpoint, which forwarded the browser to a legitimate but compromised WordPress website belonging to a South American retailer.

The compromised website then redirected the visitor to claude-desk-code[.]com, a fake Claude download page designed to trick macOS users into executing malicious commands.

Bing's click-tracking redirects use JavaScript to send visitors to their destination, allowing attackers to redirect users to malicious websites while making the traffic appear to originate from Bing.

The campaign also uses two layers of cloaking to prevent unwanted visitors from reaching the payload.

The compromised WordPress website checks for a Bing referrer and specific browser headers before redirecting visitors, while the fake Claude website uses JavaScript to verify that visitors arrived from Google or Bing.

Visitors who try to access the malicious site directly are redirected to a 404 error page, making it harder for automated security scanners to analyze the attack.

Fake Claude installer hides malicious commands

The final destination is a convincing imitation of a Claude download page that offers a macOS installer using an installation command entered into the Terminal.

However, while the page displays Anthropic's legitimate installation command, curl -fsSL https://claude.ai/install.sh | bash, clicking the copy button places a malicious command in the clipboard.

The substituted command first prints a message claiming to download Claude from Anthropic's official website, but actually decodes a Base64-encoded URL pointing to lake-90[.]com.

It then uses curl to silently download a .dat file from the attacker-controlled server and pipes its contents directly into the macOS Z shell (zsh) for execution.

This means victims see the legitimate Claude installation URL both on the download page and in the terminal, even though an entirely different script is being executed.

The final payload delivered by the attack remains unknown, so it unclear what malware, if any, is being installed.

Push Security says it identified several domains associated with the same ClickFix toolkit, which it tracks internally as AcSig, that use an identical macOS installation command, payload URL structure, and installer interface.