E-Mail Alert: Login from new device incorrect details

[ESP-Marc]

Bug Description

PostHog Cloud https://eu.posthog.com/
Received e-mail alert "We spotted a login from a new device" reporting incorrect browser and OS credentials from my own login action.

• Expected Island 1.85.25 or Chrome: 145.0.**7** on **Windows 11** instead got Chrome 145.0.**0** on **Windows 10**

Reported Location, Login Method, Time & IP6 was correct.

Information is misleading for security audits.

How to reproduce

1. Simply Login to cloud workspace (incognito / cleared browser state)
2. Wait for e-mail

Other Comments

Makes me wonder if this inaccuracy extends to PH analytical detections in general concerning Browser version and reported OS version?

Debug info

N/A

[kartik-lamkhade]

I would like to work on fixing this issue. The incorrect browser/OS information in the login alert seems reproducible, and I can investigate how the user-agent is parsed and improve the accuracy of the email report. Please let me know if this approach is acceptable.

[ESP-Marc]

I just looked at JS Navigator object, unfortunately it its self reports Windows 11 as Windows 10 NT in Chromium and Mozilla so there's nothing you can do about it, same goes for the Minor version, its simply is not accurately reported.

However on chromium browsers only, there is an extra field userAgentData, if this key exists then in access navigator.userAgentData.brands array.

{
  "userAgendData": {
    "brands": [
        {
            "brand": "Not:A-Brand",
            "version": "99"
        },
        {
            "brand": "Island",
            "version": "145"
        },
        {
            "brand": "Chromium",
            "version": "145"
        }
    ],
    "mobile": false,
    "platform": "Windows"
  }
}

The reported flavour (brand) of Chromium can at least be improved. Not sure if "Not:A-Brand" is consistent across brands like this or just a quirk of Island browser?