One of the biggest misconceptions around WebRTC is that it is “secure by default.” Browsers enforce HTTPS, media is protected with DTLS-SRTP, and modern crypto is doing its job extremely well. And yet, when real-world WebRTC deployments get compromised, it is rarely because someone cracked encryption. Far more often, the problem is much simpler and much older: passwords.
In WebRTC softphones, SIP credentials, API keys, and access tokens quietly become the most valuable assets in the system. How those credentials are created, stored, distributed, and rotated will ultimately determine whether your WebRTC deployment is resilient—or just waiting to be abused.
This article focuses entirely on password and credential security in WebRTC environments, and why it deserves far more attention than it usually gets.
The uncomfortable reality of credentials in browsers
WebRTC runs in environments that were never designed to be secret vaults. Browsers are powerful, flexible, and user-friendly, but they are also noisy and exposed. JavaScript code can be inspected. Network traffic can be observed. Browser storage is accessible to extensions. End-user devices are shared, lost, stolen, or infected far more often than engineers like to admit.
And yet, many WebRTC applications still rely on a simple pattern: place SIP usernames and passwords directly into the client and hope transport encryption is enough.
The moment a permanent credential reaches the browser, you have already lost a degree of control. Even if TLS protects it in transit, the secret still exists at rest on a device you do not manage. It may live in memory, in LocalStorage, in IndexedDB, or embedded in configuration that can be copied and reused indefinitely. From that point on, the credential can escape in ways you will never be able to fully audit.
This is not a theoretical concern. In practice, it only takes one compromised laptop, one shared workstation, or one malicious browser extension to leak credentials that can then be reused elsewhere without limitation.
Why SIP passwords are more dangerous than they look
A SIP password is not just a login detail. In many systems, it is effectively a master key.
Once an attacker has valid SIP credentials, they often gain the ability to register from anywhere in the world, impersonate a user or extension, and place calls through your infrastructure. That can quickly escalate into toll fraud, especially if international or premium routes are enabled. In some cases, attackers do not even care about calls—they use SIP credentials as a foothold to learn more about your network, your PBX behavior, and your routing rules.
What makes this particularly dangerous is that SIP environments historically grew up in a “trusted network” mindset. Passwords were often shared, reused, and rarely rotated. Many PBX systems still assume that if you have the credentials, you are allowed to do almost everything that extension can do. Least-privilege design is the exception rather than the rule.
In a WebRTC world, where endpoints are no longer desk phones on a private LAN but browsers and mobile devices on unpredictable networks, those assumptions break down very quickly.
The illusion of safety created by TLS
It is common to hear statements like, “We’re using WSS and TLS, so the credentials are secure.” While encrypted transport is essential, it solves only one piece of the problem.
TLS protects credentials while they are moving across the network. It does not protect them once they arrive at the endpoint. It does not prevent them from being copied, reused, or extracted later. And it does not help you revoke them quickly if something goes wrong.
In other words, TLS protects the pipe—but not the secret itself.
If a credential is long-lived and reusable, transport encryption alone is not enough to keep it safe in a browser-based environment.
Long-lived credentials are the real enemy
The most dangerous pattern in WebRTC security is the use of permanent or long-lived credentials on the client side. These credentials often start life as a “temporary” solution—perhaps during testing or early rollout—but quietly become permanent fixtures in production.
Once distributed, they are extremely difficult to claw back. You cannot easily invalidate a password that exists in thousands of browsers without breaking active users. This leads to hesitation around rotation, which in turn increases the window of exposure when a credential is leaked.
In contrast, short-lived credentials fundamentally change the risk profile. If a token expires quickly and is tightly scoped, its value to an attacker drops dramatically. Even if it leaks, it may only be usable for minutes or hours, and only for a specific purpose.
This shift—from permanent secrets to time-bound access—is one of the most important security improvements WebRTC platforms can make.
Separating identity from infrastructure secrets
A powerful way to reduce risk is to stop treating client identity and infrastructure access as the same thing.
When a browser registers directly to a PBX using SIP credentials, the client is effectively holding an infrastructure secret. That means the browser must be trusted not just to identify the user, but to protect the PBX itself.
A more robust approach is to let the client authenticate to a service you control, using credentials that are designed for browsers: short-lived tokens, scoped access, and strong revocation. That service can then hold the real PBX credentials on the server side, where they are never exposed to the end user.
This separation dramatically reduces the impact of client compromise. Even if a browser token is leaked, it does not automatically grant access to the PBX itself, nor does it reveal reusable SIP passwords that can be used elsewhere.
How Siperb approaches PBX password security
This is where a proxy-based architecture becomes more than just a convenience layer.
With Siperb, PBX credentials do not need to live in the browser at all. Instead of distributing SIP usernames and passwords to every WebRTC endpoint, those credentials can remain inside the proxy. The browser authenticates to Siperb using controlled, platform-level credentials, and Siperb handles the interaction with the PBX on the backend.
This approach has several important consequences. First, it significantly reduces the number of places where sensitive PBX passwords exist. Second, it allows PBX credentials to be rotated or changed without forcing updates on every client. And third, it limits what a compromised endpoint can do, because it no longer possesses the keys to the PBX directly.
From a security perspective, this shifts the most sensitive secrets away from the most exposed environment. From an operational perspective, it also simplifies onboarding and reduces the temptation to reuse or share credentials.
Security that supports scale, not just theory
Password security in WebRTC is not about perfection—it is about managing risk in environments that are inherently messy. Browsers will always be exposed. Devices will always be lost. Users will always make mistakes. The goal is to design systems that assume this reality and limit the damage when things go wrong.
By avoiding long-lived credentials in clients, separating identity from infrastructure access, and keeping PBX passwords inside controlled server-side components like a proxy, you dramatically improve your security posture without making life harder for users.
In the end, strong WebRTC security is less about exotic cryptography and more about disciplined credential design. Get that right, and most real-world attacks simply never get the opportunity to start.
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