‘Stanley’ Toolkit Turns Chrome Into Undetectable Phishing Vector

Summary

Researchers at Varonis have detailed a malware‑as‑a‑service kit called “Stanley” that produces malicious Chrome extensions capable of overlaying attacker‑controlled phishing pages on top of real websites while leaving the address bar unchanged. Sold on cybercrime forums for roughly $2,000–$6,000, Stanley includes a command‑and‑control panel for managing victims, configuring spoofed redirects and delivering fake browser notifications. The extensions can appear as innocuous tools (for example a note‑taking extension), request broad permissions, then intercept visits to targeted sites and present full‑screen iframe spoofs that capture credentials despite the legitimate URL still showing in the address bar.

Key Points

Stanley is a turnkey malware kit that generates malicious Chrome extensions and is marketed on Russian forums for $2,000–$6,000.
Extensions produced by Stanley can overlay phishing pages on genuine sites using iframes while the browser still displays the real domain in the address bar.
The kit provides a C2 panel and, at higher tiers, promises Chrome Web Store approval for created extensions, undermining typical “only install from the store” advice.
Common defences—checking the URL in the address bar, phishing‑resistant factors, and many endpoint/network controls—can be bypassed when the attacker operates inside the browser.
Practical mitigations include allow‑listing extensions, flagging or blocking excessive permissions, regular audits of employee extensions (especially on BYOD), and enforcing least privilege for browser tooling.

Context and Relevance

Browsers are now the primary workspace for most organisations: authentication, transactions and privileged actions happen in the browser, and extensions can access that activity. Stanley is not technically novel — iframe overlays, header stripping and C2 polling are known techniques — but it is significant because it weaponises the browser ecosystem itself and promises evasion of store reviews. That combination makes it a potent threat for enterprises, remote workers and anyone using SaaS apps through Chrome.

Author’s take (punchy): This one matters. Cheap, easy to use and able to sit in the Chrome Web Store alongside legitimate tools, Stanley exposes a real blind spot in many security programmes. If you rely on address‑bar checks or employee discretion, you need to revisit extension policy and monitoring now.

Why should I read this?

Quick and blunt: if you care about credentials or the security of SaaS apps, read this. Stanley shows how an extension that looks harmless can quietly phish users while the browser appears normal. It’s a reminder to sort your extension allow‑listing, tighten permissions and stop assuming the address bar is your last line of defence — otherwise you’ll be handing out compromises on a plate.

Source

Source: https://www.darkreading.com/remote-workforce/stanley-toolkit-chrome-undetectable-phishing