security

Sponsored search results lead developers straight into a ClickFix malware trap

Cybercrims are using fake OpenAI Codex download pages to trick Mac developers into running malware disguised as installation commands.

Researchers at Cato Networks uncovered the campaign after spotting sponsored Google search results targeting people looking to download Codex for macOS. The ads direct would-be users to a convincing-looking download page hosted on Google Sites, complete with the familiar OpenAI branding. There is, however, no Codex waiting at the other end.

Instead of serving up an installer, the fake site tells Mac users to open Terminal, paste in a supplied command, and run it. The instructions are dressed up as part of the installation process, but the command quietly kicks off a multi-stage malware infection.

It's a variation of the increasingly popular "ClickFix" technique, in which attackers convince victims to execute malicious commands themselves rather than relying on a dodgy attachment or executable to do the dirty work.

In this case, the command begins with what appears to be a legitimate npm instruction for installing Codex. Tacked onto it, however, is code that decodes a Base64-encoded URL, fetches an attacker-controlled shell script and pipes it into zsh.

That script pulls down another stage, which contacts the attacker's server to report that someone has taken the bait before downloading a Mach-O executable to “/tmp/helper.” It then removes security information macOS uses to flag suspicious downloads, helping the malware dodge the usual warnings before it launches.

Cato said the final binaries are universal Mach-O files, meaning they can run natively on both Intel-powered Macs and newer Apple Silicon machines.

The researchers found substantial similarities between the campaign and Atomic macOS Stealer, better known as AMOS, an infostealer previously spread through fake software downloads and malicious advertising campaigns.

Cato isn't quite ready to slap an AMOS label on the malware, but says plenty of fingerprints point in that direction, from how the attack is staged to how the final payload is built.

The crooks have also taken steps to keep researchers from getting a good look at their handiwork.

Although victims initially land on Google Sites, the malicious content itself is pulled into the page from attacker-controlled infrastructure using an iframe. That infrastructure checks details including the visitor's operating system and the path used to reach it, allowing it to show harmless-looking content when a visitor doesn't fit the profile the attackers are after.

Cato said the decoy site offered both macOS and Linux download buttons, although it only observed the malware chain being delivered to Mac users.

Codex isn't the only AI coding assistant getting this treatment. During its investigation, Cato found a similar ClickFix page masquerading as Anthropic's Claude Code and sharing infrastructure with the Codex campaign.

The attackers don't have to work particularly hard to find their victims, either. Developers searching Google for Codex do that work for them, with sponsored ads pushing the fake download page above the legitimate results. ®