Description

Security researchers have uncovered a malvertising campaign that distributes the Amatera infostealer by impersonating installation pages for the Claude Code AI developer tool. Attackers are leveraging sponsored search advertisements to redirect users to cloned documentation websites that appear nearly identical to the legitimate pages. When users copy and execute the provided installation command from these fake pages, they unknowingly download malware that steals sensitive information from their systems. The campaign uses a technique known as InstallFix, where attackers replicate official documentation pages and alter the installation command displayed to users. These malicious sites closely mimic the design, branding, and structure of the legitimate Claude Code documentation, making them difficult to distinguish from authentic sources. The attackers primarily distribute these fake pages through search engine advertisements that appear above legitimate search results for queries related to installing the Claude Code CLI or setup instructions. When a victim runs the modified command from the cloned page, it retrieves a malicious script hosted on attacker-controlled infrastructure rather than the official source. This script installs Amatera, an information-stealing malware believed to be derived from the ACR Stealer family. Once deployed, the malware collects browser credentials, authentication cookies, saved autofill data, cryptocurrency wallet details, and system information. It also uses evasion techniques such as dynamic API resolution and communication through CDN-backed infrastructure to make detection more difficult.