Can websites analyze your Hardware?

User Support General
1

Since a few days i get the following error when trying to visit mobile.de:

Access denied
Reference Error: 0.117a2617.1764711957.197945c0

Unfortunately, automated access to this page was denied.
If you are interested in accessing our data, please contact us

I tried different browsers (firefox, chrome, opera), deleting cookies/website data, no browser addons and using a VPN. → Did not solve my problem.
On my Laptop which is connected to the same fritzbox the website works without a problem. But if i use a Virtualbox Linux Mint instance on the laptop i once again get the same error message.

I contacted mobile and sent a few emails back and forth but they are just replying with generic, useless answers.

Now my desktop is a workstation with somewhat exotic hardware:

System:
  Kernel: 6.1.0-38-amd64 arch: x86_64 bits: 64 Desktop: KDE Plasma v: 5.27.5
    Distro: MX-23.6_KDE_x64 Libretto April 13 2025
Machine:
  Type: Kvm System: Supermicro product: SYS-551A-T v: 0123456789
    serial: <superuser required>
  Mobo: Supermicro model: X13SWA-TF v: 1.01 serial: <superuser required>
    UEFI: American Megatrends LLC. v: 2.1b date: 05/28/2024
CPU:
  Info: 60-core model: Intel Xeon w9-3595X bits: 64 type: MT MCP cache:
    L2: 120 MiB
  Speed (MHz): avg: 1087 min/max: 800/4600:4700:4800 cores: 1: 800 2: 800
    3: 800 4: 4089 5: 4300 6: 4136 7: 3070 8: 800 9: 4209 10: 800 11: 800
    12: 800 13: 800 14: 4220 15: 800 16: 4179 17: 800 18: 800 19: 800 20: 800
    21: 800 22: 800 23: 800 24: 800 25: 3400 26: 800 27: 800 28: 800 29: 800
    30: 800 31: 800 32: 800 33: 4215 34: 800 35: 800 36: 800 37: 800 38: 800
    39: 800 40: 800 41: 800 42: 800 43: 800 44: 800 45: 3684 46: 800 47: 3750
    48: 800 49: 800 50: 800 51: 800 52: 800 53: 800 54: 800 55: 800 56: 800
    57: 800 58: 800 59: 800 60: 800 61: 800 62: 800 63: 800 64: 800 65: 800
    66: 800 67: 800 68: 800 69: 800 70: 800 71: 800 72: 800 73: 800 74: 800
    75: 800 76: 800 77: 800 78: 800 79: 800 80: 800 81: 800 82: 800 83: 800
    84: 800 85: 800 86: 800 87: 800 88: 800 89: 800 90: 800 91: 800 92: 800
    93: 800 94: 800 95: 800 96: 800 97: 800 98: 800 99: 800 100: 800 101: 800
    102: 800 103: 800 104: 800 105: 800 106: 800 107: 800 108: 800 109: 800
    110: 800 111: 800 112: 800 113: 800 114: 800 115: 800 116: 800 117: 800
    118: 800 119: 800 120: 800
Graphics:
  Device-1: ASPEED Graphics Family driver: N/A
  Device-2: AMD Navi 31 [Radeon Pro W7800] driver: amdgpu v: kernel
  Display: x11 server: X.Org v: 1.21.1.7 with: Xwayland v: 22.1.9 driver: X:
    loaded: amdgpu unloaded: fbdev,modesetting,vesa dri: radeonsi gpu: amdgpu
    resolution: 2560x1440~60Hz
  API: OpenGL v: 4.6 Mesa 25.0.7-2~mx23ahs renderer: AMD Radeon Pro W7800
    (radeonsi navi31 LLVM 15.0.6 DRM 3.49 6.1.0-38-amd64)
Audio:
  Device-1: Intel Alder Lake-S HD Audio driver: snd_hda_intel
  Device-2: AMD Navi 31 HDMI/DP Audio driver: snd_hda_intel
  Device-3: VIA VT1720/24 [Envy24PT/HT] PCI Multi-Channel Audio
    driver: snd_ice1724
  API: ALSA v: k6.1.0-38-amd64 status: kernel-api
  Server-1: PipeWire v: 1.0.0 status: active
Network:
  Device-1: Intel I210 Gigabit Network driver: igb
  IF: eth0 state: down mac: <filter>
  Device-2: Aquantia AQC113C NBase-T/IEEE 802.3an Ethernet [Marvell
    Scalable mGig] driver: atlantic
  IF: eth1 state: up speed: 1000 Mbps duplex: full mac: <filter>
  Device-3: Intel Ethernet X550 driver: ixgbe
  IF: eth2 state: down mac: <filter>
  Device-4: Intel Ethernet X550 driver: ixgbe
  IF: eth3 state: down mac: <filter>
  IF-ID-1: usb0 state: unknown speed: -1 duplex: half mac: <filter>
Bluetooth:
  Device-1: Insyde RNDIS/Ethernet Gadget type: USB driver: rndis_host
Drives:
  Local Storage: total: 86.88 TiB used: 12.42 TiB (14.3%)
  ID-1: /dev/nvme0n1 vendor: Micron model: 7450 MTFDKBG3T8TFR size: 3.49 TiB
  ID-2: /dev/nvme1n1 vendor: Micron model: 7450 MTFDKBG3T8TFR size: 3.49 TiB
  ID-3: /dev/nvme2n1 vendor: Micron model: 7450 MTFDKBG3T8TFR size: 3.49 TiB
  ID-4: /dev/sda vendor: Seagate model: ST22000NM001E-3HM103 size: 20.01 TiB
  ID-5: /dev/sdb vendor: Seagate model: ST22000NM001E-3HM103 size: 20.01 TiB
  ID-6: /dev/sdc type: USB vendor: Seagate model: ST20000NM007D-3DJ103
    size: 18.19 TiB
  ID-7: /dev/sdd type: USB vendor: Seagate model: ST20000NM007D-3DJ103
    size: 18.19 TiB
Partition:
  ID-1: / size: 3.44 TiB used: 146.96 GiB (4.2%) fs: ext4 dev: /dev/nvme0n1p2
  ID-2: /boot/efi size: 252 MiB used: 274 KiB (0.1%) fs: vfat
    dev: /dev/nvme0n1p1
Swap:
  ID-1: swap-1 type: file size: 22 GiB used: 0 KiB (0.0%) file: /swap/swap
Sensors:
  System Temperatures: cpu: 46.0 C mobo: N/A gpu: amdgpu temp: 39.0 C
  Fan Speeds (RPM): N/A gpu: amdgpu fan: 1024
Info:
  Processes: 1147 Uptime: 20d 6h 14m Memory: 503.33 GiB used: 14.52 GiB (2.9%)
  Shell: Bash inxi: 3.3.26

According to ChatGPT it is possible for websites to analyze my hardware and then
flag me as a “bot” because what i’m using looks more like a server than a desktop machine.
I never heard of or seen that though.

ChatGPT also suggested using LibreWolf because that would kinda “hide/fake” my hardware and sure enough that works.
When using LibreWolf i can visit mobile.de but not if i use regular firefox.
But using 2 browsers is impractical and according to ChatGPT websites can also detect how many cpu cores i have etc. and this is apparently information that LibreWolf can’t hide.
So its probably only a matter of time until this “fix” stops working.

So is this real and something new, up and coming for the year 2026?
Do i have to worry that more and more websites will adapt this kind of technology starting in 2026?

Or is something completely different going on?
But it sure looks like they really analyze visitors hardware.

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It’s Firefox problem.

I’ve loaded it once with normal firefox on disposable VM with fresh profile and noscript disabled. But it was once. When started testing with other settings it denied. Deleting profile, disabling noscript, changing VPN endpoint did nothing.

But on Donut Browser with Camoufox (hardened Firefox fork) and even with static profile and noscript with default deny settings it loads no problem.

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Here’s what i just found out…

If i do the following in Firefox ESR then mobilede works again:

1. about:config

2. privacy.resistFingerprinting -> Set to: true

3. Restart Firefox ESR

4. Navigate to "mobile.de" (or any website that blocks you based on fingerprint)

5. Delete Cookies/Website Data from mobile.de (or any website that blocks you based on fingerprint)

6. Reload Page (F5)

7. privacy.resistFingerprinting -> Set to: false

8. Restart Firefox ESR

Note that i do revert the privacy.resistFingerprinting at the end but mobilede keeps working UNLESS i delete the cookies again.

Do you guys think they use Fingerprinting the first time someone visits their site and then set a cookie that determines if you are blocked or not?

At first i thought it might only be WebGL Fingerprinting:
https://www.zenrows.com/blog/webgl-fingerprinting#what-is-webgl-fingerprinting

But doing this

1. google-chrome --disable-webgl or --disable-3d-apis

2. Navigate to "mobile.de" (or any website that blocks you based on fingerprint)

3. Delete Cookies/Website Data from mobile.de (or any website that blocks you based on fingerprint)

4. Reload Page (F5)

Source: WebGL Browser Report - WebGL Fingerprinting - BrowserLeaks

Disables WebGL but does not fix the problem. So they are obviously looking at more than just WebGL when creating their fingerprint.

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See also:

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I use the Mullvad Browser, which is also a harden Firefox browser and has all the about:config settings already configured.

It works with mobile.de also.

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