Surfshark review: quiet at idle, but its kill switch slips at startup

Who this is for

Surfshark suits people who want a VPN that stays out of the way: in our tests it was the quietest VPN app while idle, and it opened nothing to the network. Connected, it leaked nothing.

Its weak spot is what happens when something goes wrong. The Kill Switch is off by default. With it off, a crashed VPN service let our real IP out for about 5 seconds. With it on, a crash was handled cleanly, but a Windows restart still let our IP and several Windows apps out for about 8 seconds before the tunnel came up.

We tested Surfshark 6.21 on the Surfshark One plan (1 month), on 4 November 2026, on Windows 11 in a virtual machine on an EU internet connection. Surfshark is owned by Nord Security, the company behind NordVPN, and we ran both through the same tests.

What it installs

We took a full snapshot of the system before installing and after, and compared them. The installer came from Surfshark’s own download server through Windows Package Manager, with a verified hash, and is signed by Surfshark.

Installing added:

• one Windows service, Surfshark Service, running as SYSTEM and starting with Windows;
• two drivers: SharkDivert (Surfshark’s packet driver, used for split tunneling) and OpenVPN Data Channel Offload, plus an OpenVPN network adapter;
• an autostart entry for the app;
• a private copy of .NET inside the program folder, so nothing shared was added to Windows.

A WireGuard service and adapter appear when you connect. Files for a webcam-protection driver and Avira’s antivirus engine sit in the program folder but are not active until you turn those features on. Six root certificates appeared during installation; Windows’ event log shows Windows itself downloaded them.

The first launch opens a setup screen with a large Start button that turns on the antivirus, web content blocker and other extras, and a small Exit setup link. We chose Exit setup.

Defaults after signing in: Kill Switch off, CleanWeb off, auto-connect off, protocol automatic (WireGuard).

Who it talks to

We logged every outgoing connection with Windows firewall auditing for 15 minutes while the app was open, signed in and disconnected.

There were 10 connections, all from the app window: five to Surfshark’s servers through the CDN77 network and five DNS-over-HTTPS lookups to Cloudflare. The VPN service made none. That is the quietest result we have recorded; NordVPN made 74 in the same test, Proton VPN one.

Surfshark never asked about analytics or crash reports. Under Settings → App settings, Send crash reports is on by default. The app bundles the Sentry error-reporting SDK, and its files sit in Surfshark’s data folders. We saw no connection to Sentry while idle, but a crash would be reported unless you switch it off.

The service listens only on the computer itself (127.0.0.1), and Surfshark adds no inbound firewall rules. We found neither our real IP nor any e-mail address in its log and settings files; the settings files are encrypted.

The app used about 580 MB of memory while idle, about 370 MB of it in the app window.

NordVPN 8.14.4990 MB

Surfshark 6.21 (VPN only)580 MB

Proton VPN 5.1.8550 MB

ZeroTier One 1.16.240 MB

Leaks

Connected to New York with default settings:

• IP: three independent IP-check services all saw the VPN’s address, which is registered in New York.
• DNS: Windows sent queries to Surfshark’s DNS servers, and both Google’s and Akamai’s resolvers saw a VPN address.
• WebRTC: Google’s and Cloudflare’s STUN servers both saw the VPN address.
• IPv6: our connection has no IPv6, so we could not test it.

No leaks.

Kill switch

We sent a request every 0.3–0.6 seconds for two minutes while breaking the connection, and counted any request that left with our real IP.

What we did	Kill switch off (default)	Kill switch on
Disabled the network for 15 s	No leak	No leak
Force-closed the app window	No leak	No leak
Force-killed the VPN service	Leaked ~5 s (10 requests), then reconnected	No leak; blocked ~10 s, then reconnected
Windows restart	n/a	Leaked ~8 s (14 requests) before the tunnel came up

The service restarts itself after a crash, which keeps outages short. But with the kill switch off, traffic flows outside the tunnel until it does. Proton VPN’s default kill switch behaved the same way for about 9 seconds; NordVPN’s blocked everything (Proton VPN review, NordVPN review).

The restart test is the bigger issue. Auto-connect was off, but Surfshark reconnected to the last server by itself after Windows restarted. Before the tunnel was up, 14 requests left with our real IP over about 8 seconds, and Windows services, Edge’s WebView2, background downloads and Game Bar all reached the internet. NordVPN’s kill switch held through the same test.

CleanWeb

CleanWeb blocks ads, trackers and malicious sites while the VPN is connected. It is off by default. We checked the same list we used for NordVPN with the VPN connected, first with CleanWeb off and then on.

VPN connected	CleanWeb off	CleanWeb on
Ad domains blocked	0 of 12	6 of 12
Tracker domains blocked	0 of 10	7 of 10
Phishing and malware test domains, pages and file blocked	0 of 7	0 of 7
Ordinary sites still working	4 of 4	4 of 4

CleanWeb switches to filtering DNS servers and answers blocked names with 127.0.0.1. It missed doubleclick.net, Google Analytics, Facebook’s tracking script, AppNexus, Amazon’s ad server, Yahoo ads and Segment. NordVPN’s Basic-plan filter blocked 16 of the same 22.

The antivirus

Surfshark One includes an antivirus. Turning it on downloads and installs a separate ~200 MB program, Avira’s “Endpoint Protection SDK”, then runs a quick scan (5 minutes, 8,371 files in our VM).

It adds a lot to Windows:

• three more services, two of them running as SYSTEM;
• eight Avira drivers, including an Early Launch Anti-Malware driver that loads before most of Windows, real-time file filters and network filters; Windows’ firewall filter count rose from 576 to 799;
• a root certificate, “Surfshark NetProtection Root 3”, in both the computer’s and the user’s trusted root stores, valid until 2066 with no restrictions;
• at least 230 MB more memory for the antivirus service alone.

A root certificate lets software vouch for any website. We checked five sites (Google, GitHub, PayPal, Wikipedia, example.com) and all showed their real certificates, so it was not intercepting ordinary browsing. But when we fetched the EICAR test file over HTTPS, the antivirus answered the secure connection itself with a “Malicious website ahead!” page, which it can only do with that certificate.

Windows Defender switched itself off while Surfshark’s antivirus was installed, which is normal when another antivirus registers. The antivirus caught the EICAR test file when it was opened and quarantined it within about 2 seconds, and blocked the download.

What it leaves behind

We uninstalled Surfshark the normal way, with the Kill Switch on and the antivirus installed. The uninstaller ran for 17 seconds and removed the app, the antivirus, all eight Avira drivers and the root certificate. Windows Defender turned itself back on. The internet came back within about a minute of the uninstaller finishing.

Left behind:

• two firewall rules, “Surfshark Block All IPv6”, inbound and outbound, which keep blocking all IPv6 traffic on the computer;
• a startup entry pointing to the deleted Surfshark program;
• the WireGuard network driver.

If you uninstall Surfshark, delete the two firewall rules in Windows Defender Firewall’s advanced settings, or IPv6 stays off.

Server locations

Every exit address we saw while connected to “New York” (four in total, on Datacamp and M247 networks) is registered in New York.

Company, audits and price

These facts come from public sources and are not test results.

Surfshark operates out of the Netherlands, which belongs to the Nine Eyes intelligence-sharing group, so Dutch authorities can legally request data (Security.org). It merged with Nord Security, the company behind NordVPN, in 2022, while keeping a separate brand (ProxyHorizon).

Deloitte verified Surfshark’s no-logs statement again in a report published in June 2025, following an earlier Deloitte review in January 2023. The assessment covered standard, static and multiport servers and their configuration, under ISAE 3000. Customers can read the report in their Surfshark account (Surfshark).

Plan	Listed price, 2-year plan	Listed renewal
Starter	$2.49/month	$79/year
One	$2.79/month	$99/year
One+	$4.49/month	$119/year

Prices as captured on 27 September 2026, with the first term running 27 months. All plans allow unlimited devices on one account, cut to 3 during a free trial, and include a 30-day money-back guarantee (ProxyHorizon).

The monthly plan we bought cost €19.95 for Surfshark One (EU price, 4 November 2026).

How to set it up safely

1. Install from surfshark.com or with winget install Surfshark.Surfshark.
2. In Settings → VPN settings, turn on Kill Switch.
3. In Settings → App settings, decide whether to keep Send crash reports on.
4. If you turn on the antivirus, know that it installs Avira’s engine, eight drivers and a root certificate.

Sources

• Surfshark: no-logs policy verified by Deloitte
• ProxyHorizon: Surfshark pricing
• Security.org: Surfshark review