Is Network Defence safe?

Medium risk

Network Defence fetches an affiliate store list from its server and opens hidden affiliate links on matching sites.

On every page, the extension requests a list of stores and affiliate links from its remote server. When the page URL contains a listed store name, it opens a small popup to a server-supplied affiliate link, redirects it to the store after a few seconds, and closes it. The extension's description does not mention this behavior, and the server controls which sites and links are used.

Strong link to a flagged operator: 1 of the 1 other listing from the same operator is rated high or critical for malicious behaviour. Flagged: Watch Party (high).

Underpin Extensionsv1.2.0Chrome Web Store
49Risk
Who publishes it

Underpin Extensions - 1 other listing from the same operator, 1 of them carrying a finding

What this publisher told the store about itself, and the other listings that told it the same thing.

Publisher
Underpin Extensions

Same store account

1 other listing published from this account, 5k+ users between them. 1 of them carries a finding.

AI-generated. Findings may contain errors. Those marked Verified have been manually reviewed.

Publishers can request a review.

Findings

Site blocker opens affiliate popups when you visit stores on a remote list

Code analysis shows a script on every page fetches a store list from a remote server and, on a URL match, opens a popup to an affiliate link, then redirects it to the store.

Severity
High unwanted
Type
Unexpected
CWE
CWE-829
Source
Static analysis
What actually happens
You did this

You open a page whose address contains a listed store name.

The extension did this

The extension opens a popup to an affiliate link, then sends it on to the store.

Fields in each remote store record
  • storeName
    example-store.com

    Text matched against the address of the page you are on.

  • affilateLink
    https://affiliate-network.example/track?id=1234

    The affiliate link opened first in the popup.

  • affilatedStore
    https://example-store.com/

    The store page the popup is redirected to after 3 seconds.

  • time
    7

    Days to wait before the same rule fires again in this browser.

The code that does this

Match, popup, redirect and close logic in contentScript.js

Readable version

Match and popup handlers

contentScript.js
        }))      }), []);      const t = (e, t) => {          console.log(e);          const r = window.location.href,            o = e.findIndex((e => r.includes(e.storeName))); - 1 !== o && n(e[o], t[0])        },        n = (e, t) => {          const n = null == e ? void 0 : e._id,            r = 864e5 * (null == e ? void 0 : e.time),            o = localStorage.getItem(n),            a = Date.now();          if (e && (!o || a - Number(o) > r && e._id === n))            if (t.switchOne) {              const t = window.open(e.affilateLink, "_blank");              t.blur(), localStorage.setItem(n, String(a)), setTimeout((() => {                t.location.replace(e.affilatedStore), setTimeout((() => {                  t.close()                }), 5e3)              }), 3e3)            } else {              if (!t.switchTwo) return;              {                const t = "menubar=10,location=0,resizable=0,scrollbars=0,status=0,width=10,height=10",                  r = window.open(e.affilateLink, "popup", t);                localStorage.setItem(n, String(a)), setTimeout((() => {                  r.location.replace(e.affilatedStore), setTimeout((() => {                    r.close()                  }), 5e3)                }), 3e3)              }            }        };
Server the content script contacts
    • extensions-stores-admin.onrender.com

    Hosted on Render; supplies the store list (/all) and the on/off switches (/allSwitches).

Observation

The extension is described as site blocking and password protection. Its listing does not mention affiliate behaviour. This is code analysis only; no live store list or popup was captured.

Observation

Static analysis finding. This behaviour was identified by reading the shipped extension code and has not yet been reproduced in a live run. The trigger conditions and the exact data sent are read from the code, not from an observed capture.

Where it sends data

Destinations our analysis observed Network Defence contacting. Sending data somewhere is not a finding on its own - an extension that syncs your settings has to talk to its own server - but it is where your data can go, and who else it goes to.

  • extensions-stores-admin.onrender.com

    Network Defence sends data to extensions-stores-admin.onrender.com. No other extension we have analysed sends data here.

Updated 15 October 2026jcfohjogleiklndicglfeeccckkdgbdn