Last updated: September 29, 2026 at 8:42 AM UTC
All 891 Vulnerability 357 Breach 144 Threat 383 Defense 7
Tag: fake-captcha (4 articles)Clear

ClickFix campaign hides its command server on the Polygon blockchain

Researchers at GuidePoint found a ClickFix campaign that compromised at least 31 organizations' websites and abuses the Polygon blockchain to run its command-and-control, a technique called EtherHiding. Visitors arriving from search engines hit a fake human-verification prompt that abuses Cloudflare's overlay and tells them to paste a command, which installs a persistent backdoor. Instead of a fixed server address that defenders can block, the backdoor fetches its current instructions from a Polygon smart contract every minute, giving the attacker a censorship-resistant, easily updated address book. This breaks the usual defense of blocking a hardcoded command server, so defenders should focus on behavior and audit their public-facing sites.

Check
Teach users that no verification prompt should ask them to paste commands, audit public-facing websites for injected scripts, and hunt for backdoors that resolve command servers through blockchain queries.
Affected
Organizations whose websites are compromised to serve the fake verification lure, and users tricked into running the pasted command; the resulting backdoor persists and pulls updatable instructions from the blockchain.
Fix
Detect on behavior rather than static addresses, block or flag outbound blockchain-resolution queries from endpoints, monitor for domain-generation patterns, continuously audit websites for injected code, and train users against paste-a-command verification tricks.

TerminalFix tricks users with fake CAPTCHAs into pasting a backdoor command

A social-engineering campaign dubbed TerminalFix uses fake Cloudflare CAPTCHA pages, often served from compromised websites, to trick visitors into copying and running a malicious PowerShell command in their terminal. It is a refined take on the ClickFix technique, tuned to make complex scripts run more reliably, and it deploys a reverse-tunnel backdoor through a multi-stage chain involving DLL sideloading, hiding payloads inside images, and an outbound WebSocket connection for command and control. The campaign has hit organizations across several sectors. The core deception is simple to teach against: a legitimate CAPTCHA never asks you to paste and run commands in a terminal or Run dialog.

Check
Warn users that no real CAPTCHA ever asks them to paste commands into a terminal, and treat any such prompt as an attack, closing the page and reporting it.
Affected
Users lured to compromised or malicious sites showing fake CAPTCHA verification; following the prompt to run a PowerShell command installs a reverse-tunnel backdoor that gives attackers remote access to the device.
Fix
Enforce application control and PowerShell script-block logging, monitor for anomalous outbound WebSocket traffic and DLL sideloading, restrict who can run scripts, and train users to recognize fake CAPTCHA and ClickFix lures.

Attackers abuse npm and its mirrors to host fake CAPTCHA phishing pages

Researchers at OX Security found a campaign using two dozen npm packages as free phishing infrastructure rather than as malware aimed at developers. Each package is just a single HTML page, harmless to install, but once served through npm content-delivery mirrors like unpkg it becomes a live, fully rendered fake Cloudflare CAPTCHA page hosted on a trusted domain. The page then redirects victims to ClickFix-style phishing infrastructure, and while it currently forwards to a legitimate site, it can be reconfigured to deliver any phishing payload. The trick is not infecting people who install the packages, but abusing the registry and its mirrors as validated, reputable storage for attacker content.

Check
Treat fake CAPTCHA and ClickFix pages as hostile even when served from trusted domains like unpkg, and educate users not to run commands or steps a CAPTCHA prompt tells them to perform.
Affected
Anyone lured to a fake CAPTCHA page hosted on a trusted npm mirror; the pages redirect to ClickFix phishing, exploiting the reputation of legitimate infrastructure to bypass suspicion and some blocking.
Fix
Monitor and filter for HTML content served from package-mirror domains, block known phishing and ClickFix infrastructure, apply reputation-aware web filtering rather than trusting domains outright, and train users on fake CAPTCHA lures.

Telecom fraud campaign uses fake CAPTCHAs to trick people into sending SMS to premium-rate numbers in 17 countries - 50+ international charges per victim

Infoblox documented a telecom fraud campaign active since June 2020 that uses fake CAPTCHA verification pages to trick mobile users into sending SMS to premium-rate numbers, racking up dozens of international charges per victim. The operation runs across 35 phone numbers in 17 countries with high-fee destinations like Azerbaijan and Kazakhstan. Each fake CAPTCHA pre-populates the SMS field with a dozen recipients - so one tap charges the victim for 50+ international texts. Charges show up on bills weeks later, long after the fake CAPTCHA is forgotten. A separate finding: 120+ campaigns abusing the legitimate Keitaro traffic-distribution tool to route victims into the same scams plus crypto wallet-drainers.

Check
Brief mobile-using staff that any 'CAPTCHA' asking them to send a text message is a scam, regardless of what brand or service the page claims to represent.
Affected
Mobile users in any region, particularly those who hit ad-tracker links from social media (Facebook ads were a primary entry point in the Keitaro variant). Corporate phones with international SMS allowed by default are at acute risk because charges may not appear until the next monthly bill cycle and may run into thousands of dollars.
Fix
On corporate mobile fleets, disable international SMS by default and enable only on request with a documented business reason - this stops the fraud at the carrier level. Audit recent corporate-phone bills for unexpected international SMS charges. Brief staff that real CAPTCHAs never ask for an SMS. Block known Keitaro TDS domains at the corporate DNS resolver.