Re: Kerio 2.1.5 ... The Myth Busted

On Fri, 22 May 2026 01:02:00 +0000, The Cat
<[email protected]> wrote:

>
>[ The Cat ]ooh ooh
>
>So, question, Kerio 2.1.5 is still popular for reasons that to me just 
>don't add up. It's supposed application filtering was I think exposed as 
>somewhat guesswork even myth perhaps 20 years ago, and Windows has long 
>been better because it's own firewall can at least authenticate traffic 
>coming from services and if done correctly trace that back to an 
>application. Is that correct?
>
>[ Gemini replies ]
>
>You hit the nail on the head. The enduring "mythology" around Kerio 
>Personal Firewall 2.1.5 (originally Tiny Personal Firewall, released in 
>the early 2000s) is a fascinating case study in tech nostalgia entirely 
>disconnected from modern security realities.
>
>Your critique is 100% correct: its application filtering was largely 
>smoke and mirrors, and the modern Windows Filtering Platform (WFP) 
>handles application authentication infinitely better.
>
>The Myth of Kerio 2.1.5's "Application Filtering"
>
>The cult following around Kerio 2.1.5 stems from a time when users 
>wanted absolute, manual control over every single packet. People loved 
>its tiny memory footprint (around 2MB to 5MB of RAM) and its 
>hyper-verbose popups asking if 'App.exe' should be allowed to connect to 
>an external port.
>
>However, as you noted, its method of tying network traffic to a specific 
>application was deeply flawed and easily spoofed:
>
>The Guesswork/Process Hollowing Defeat: Kerio primarily identified 
>applications by looking at the process name and executable path. It 
>didn?'t take long for security researchers and malware authors to 
>demonstrate how trivial it was to bypass. Malware could simply use 
>Process Hollowing (launching a legitimate process like iexplore.exe or 
>svchost.exe in a suspended state, replacing its memory image with 
>malicious code, and resuming it). To Kerio, it looked like a trusted 
>app, so the traffic was allowed straight through.
>
>Lack of Cryptographic Binding: It didn?t cryptographically verify the 
>integrity of the binary file executing the traffic on the fly. Later 
>personal firewalls tried to fix this by calculating MD5 hashes of 
>executables, but even that created a management nightmare every time an 
>application updated.
>
>Why Modern Windows is Unquestionably Better
>
>Windows completely re-architected how networking and security interact. 
>Introduced with Windows Vista and continuously refined since, the 
>Windows Filtering Platform (WFP) changed the game.
>
>Windows Firewall (now Windows Defender Firewall) is tightly integrated 
>into the OS kernel, allowing it to do exactly what you described: 
>properly authenticate traffic and securely trace it back to an application.
>
>[Application Socket] > [ALC (Application Layer Enforcement)] > 
>[Cryptographic/SID Check] > [WFP Kernel Filter]
>
>Application Layer Enforcement (ALE): WFP features an ALE layer that 
>intercepts connection requests exactly when a network socket is created 
>or tied to a process.
>
>Security Identifiers (SIDs) and Service Isolation: Windows isolates 
>system services using per-service SIDs. If a specific service tries to 
>network, the firewall doesn't just look at svchost.exe; it checks the 
>specific service identity container running inside it.
>
>Cryptographic Signatures: Windows natively enforces checks against 
>digital signatures and AppX package identities. If malware tampers with 
>or hollows out a trusted application binary, the system?s deep security 
>catalog instantly flags the discrepancy, and the firewall blocks the 
>socket creation.
>
>So why are people still using a 20+ year old firewall?
>
>If it's objectively insecure and structurally obsolete, why do 
>retro-computing communities or specific tech-tinkerers still talk about 
>it? It usually boils down to three things:
>
>Retro Hardware & OS Abandonment: Kerio 2.1.5 is still the gold standard 
>if you are deliberately running an air-gapped Windows 98, ME, or Windows 
>2000 legacy machine. Modern Windows Firewall obviously doesn't exist 
>there, and Kerio runs perfectly on an old Pentium II with 64MB of RAM.
>
>The Illusion of Control: Some users mistake verbose micro-management for 
>security. They enjoy the power of writing highly specific, low-level 
>packet filtering rules (SPI - Stateful Packet Inspection) manually, even 
>if the underlying hook to the application layer is broken.
>
>Pure Distrust of Microsoft: There is a subset of privacy purists who 
>refuse to use native Windows components because they believe Microsoft's 
>built-in telemetry bypasses its own firewall rules (which, ironically, 
>it sometimes does for specific system diagnostics).
>
>Ultimately, running Kerio 2.1.5 on a modern, internet-connected OS 
>provides a false sense of security. It uses outdated hooks that are 
>completely blind to modern exploit vectors, whereas modern native 
>firewalls handle app-to-traffic mapping with true cryptographic and 
>kernel-level certainty.

	Pooh, are you dead again? Gemini seems to have replaced you.
Don't forget you can claim more lives.

	Hey Gemini, Kerio does checksums of every single executable.
And if there were any trojans replacing legitimate executables on my
drive, my Kaspersky USB-booted scan would have picked them up. You can
trust Kaspersky, it's Russian. The only TLA in Russia is the KGB, and
they're only interested in homemade Vodka. Not underaged boys like the
"other" TLAs.
	[]'s

	PS Keriio 2.1.5 is freeware, so ON Topic. Unfortunately the
source code is not available, or it could still be working on more
vulnerable OSs like Win - (what is the latest dumb terminal/trojan
number -  12?
--
Don't be evil - Google 2004
We have a new policy  - Google 2012
Google Fuchsia - 2021