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02/08/2026 11:40 am
TL;DR: Browser extensions can read page content, intercept network traffic, and persist through silent updates, making authenticated browser sessions a high-value target for attackers, according to Aikido. The control gap is not awareness but governance: manual allowlists and endpoint tools miss behavior change, ownership transfer, and browser-native abuse.
NHIMG editorial — based on content published by Aikido: Why browser extensions are a major security risk and what you can do about it
Questions worth separating out
Q: How should security teams govern browser extensions that access SaaS data?
A: Treat browser extensions as access-bearing non-human identities.
Q: Why do browser extensions increase the risk of session theft and token abuse?
A: Because they can operate inside the browser process, where session cookies, OAuth tokens, page content, and form data already exist in usable form.
Q: What do organisations get wrong about extension allowlists?
A: They assume a reviewed extension stays the same after install.
Practitioner guidance
- Inventory every browser extension in developer and privileged user profiles Build a current list of installed extensions across managed devices, grouped by browser profile and user role.
- Replace static allowlists with live install blocking and behaviour monitoring Use a continuously updated threat feed to block known malicious extensions before install, then monitor runtime behaviour for changes in network requests, permission use, and access to session data.
- Separate privileged browsing from general browsing Force sensitive work into isolated browser profiles so a compromised extension cannot reuse the same session context across personal and work activity.
What's in the full article
Aikido's full article covers the operational detail this post intentionally leaves for the source:
- Permission-by-permission review guidance for browser extensions used by developers and privileged users
- Operational examples of how malicious or compromised extensions exfiltrate cookies, tokens, and page content
- Browser profile and policy patterns that reduce blast radius without blocking every extension
- Detection and enforcement approaches for teams that need to monitor extension behaviour at scale
👉 Read Aikido's analysis of browser extension security risk and session theft →
Browser extensions and session theft: are your controls keeping up?
Explore further
02/08/2026 12:53 pm
Browser extensions have become an identity control problem, not just an endpoint problem. The article is right to focus on browser-native access because extensions now sit next to the systems where human users and service identities authenticate. Once an extension can read session data or OAuth material, the trust boundary shifts from the browser vendor to the extension lifecycle. Practitioners should treat extension governance as part of access governance, not as a separate hygiene task.
A question worth separating out:
Q: How should teams respond if a browser extension is suspected of exfiltrating data?
A: Revoke the extension, isolate affected browser profiles, and review all session tokens, OAuth grants, and privileged logins that may have passed through the browser while the extension was active. Then check whether any downstream systems accepted replayed cookies or token-based access from outside expected geographies or devices.
👉 Read our full editorial: Browser extension security risk exposes authenticated browser sessions
