Know Your Enemy: Browser-Based Attack Techniques in 2026

Given that the browser is where business apps are accessed and used, it makes sense that attacks are happening there too. Most breaches today begin in a browser session. Often, they never leave it, with the entire attack chain from initial access to exfiltration playing out in the browser.

Here are the six most dangerous techniques that should be on every security team's radar in 2026.

1. Phishing for credentials and sessions

Modern phishing kits don't just steal passwords — they intercept live sessions. Reverse-proxy adversary-in-the-middle (AiTM) kits like Tycoon2FA, Sneaky2FA, and Evilginx relay credentials and session tokens in real time, bypassing most forms of MFA. These kits are sold as turnkey Phishing-as-a-Service platforms with anti-bot protection, dynamic lure generation, and automated session replay — reducing the barrier to sophisticated phishing to effectively zero.

At the same time, phishing delivery has moved well beyond email — attackers deliver links over instant messaging, social media, SMS, malicious ads, and in-app messaging. According to Push data, roughly 1 in every 2 phishing attacks is delivered outside of email entirely. And with 89% of phishing domains active for fewer than two days, organizations relying on blocklists are playing a losing game.

2. Malicious copy and paste (ClickFix)

Since late 2024, attackers have been tricking users into copying and executing malicious commands under the pretext of "fixing" an issue — most commonly a fake CAPTCHA or verification challenge. Microsoft's Digital Defense Report identified ClickFix as the most common initial access vector, accounting for 47% of observed attacks. ClickFix became the dominant technique in Push detections for the first time in Q2 2026, reaching 52% of total detections.

ClickFix is a hybrid of browser and endpoint targeting — the lure is delivered via the browser, but the user copies and runs malicious scripts locally, typically installing Remote Access Tools or infostealer malware. Four in five ClickFix payloads intercepted by Push are accessed from search engines via compromised sites, malvertising, and SEO poisoning, completely bypassing email security.

The technique continues to evolve. InstallFix uses malvertised fake install pages for developer tools like Claude Code and NotebookLM, where the install command has been replaced with a malicious one. The LLMShare campaign used shared conversations on AI chatbot platforms to deliver malware via pages hosted on trusted domains. But every variant shares one thing: a malicious copy-and-paste event in the browser.

3. Authorization phishing

A growing class of attacks targets what happens after the login. Instead of stealing a session from the authentication flow, authorization phishing abuses OAuth mechanisms — consent grants, device code flows, and token exchanges — to obtain access tokens. The attacker never touches the authentication flow, which means every form of MFA, including phishing-resistant passkeys, is irrelevant.

Three techniques currently fall under this umbrella. Consent phishing sees the victim authorize a malicious third-party app via an OAuth consent grant. Device code phishing abuses the RFC 8628 device authorization grant to circumvent standard authentication entirely — Push now tracks 30+ distinct kits offering the technique. ConsentFix is a ClickFix-OAuth hybrid first observed in Russian APT29 campaigns that has since been commoditized into criminal tooling.

4. Malicious browser extensions

Attackers use malicious extensions to steal data, log keystrokes, and intercept credentials and tokens as they transit the browser. Most malicious extensions didn't start that way — attackers acquire legitimate extensions and wait until install counts reach maximum impact before deploying a malicious update.

An analysis across Push customers found that 46.76% of extensions have the permission combinations needed for account takeover with no user interaction. AI browser extensions add a further dimension — the Verizon DBIR 2026 found that more than 15% of corporate users had unauthorized AI browser extensions installed, and Push found an average of 17 unique AI extensions per company (with one team running 163), creating data exfiltration pathways independent of traditional DLP controls.

Static risk scoring is a poor predictor of supply chain compromise — every major extension breach of the past 18 months involved extensions that scored as low-risk beforehand. A default-deny approach with allowlisting plus monitoring for change events is more effective than risk-score-based removal.

5. Credential stuffing and ghost logins

Password-based compromise remains one of the leading causes of breaches, which might surprise you if you think SSO solved credential attacks. But SSO isn't universal — SAML often costs extra, self-adopted apps rarely get configured, and most apps allow simultaneous login methods. The result is ghost logins: backup credentials outside SSO, invisible to IdP logs, created at adoption and still active unless explicitly disabled.

Of the last million logins observed by Push, 1 in 4 were password logins (not SSO), 2 in 5 were not protected by MFA, and 1 in 5 used a weak, breached, or reused password. Cloudflare's 2026 Threat Report found that 63% of all human logins involve credentials already compromised elsewhere.

6. Session hijacking

Session hijacking allows attackers to bypass authentication entirely by taking a stolen session token and replaying it in their own browser. This defeats even phishing-resistant controls like passkeys, because the authentication step has already been completed.

The most prominent source of stolen tokens is infostealer malware, which ClickFix is now the primary delivery mechanism for. The Verizon DBIR 2025 found that 46% of infostealer infections leading to corporate breaches originate on non-managed devices — personal machines, developer workstations, and contractor laptops where EDR is absent. Browser sync features create another bridge, meaning personal account compromises can directly lead to corporate breaches.

Where this leaves security teams

These six attack categories all play out inside the browser, exploiting gaps in traditional security tools that operate at the email, network, or endpoint layers.

For more detail on each of these attack techniques, how they work in the wild, and what you can do about them, check out the guide to 2026 Browser Attack Techniques from Push Security.

Push Security is a browser-based threat detection and response platform that detects and blocks these attacks in real time, deployed as a lightweight browser extension with no browser migration required. Security teams use Push to detect and stop advanced browser-based attacks like AiTM phishing, ClickFix, and session hijacking; gain visibility and control over browser extensions and AI tool usage; and harden identities by surfacing credential reuse, SSO gaps, and shadow IT.

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