The SIM Card Hack You’re Not Supposed to Know About

SIMjacker Overview

SIMjacker is an attack that abuses software on some SIM cards to send commands to a phone without the user’s knowledge.

SIM cards can run software, with processing, memory, storage, and an operating system. That software can communicate with a phone through the SIM Toolkit (STK), a standard feature intended for carrier services.

How the Attack Works

A vulnerable SIM applet called the S@T Browser can process specially formatted binary SMS messages. The video describes a zero-click sequence:

1. An attacker sends a hidden command.
2. The SIM processes it.
3. The phone may be instructed to return information—such as location data or the device’s IMEI—through another silent message.

The video gives example payload values, including 0xD1, 0x10, and 0x11, as command indicators.

Why Phone Protections May Not Stop It

According to the narrator, SIM Toolkit commands may be handled through the phone’s modem or baseband rather than ordinary apps. As a result, operating-system permissions and app sandboxing may not apply in the usual way.

Potential Attackers and Persistence

The video says launching this type of attack requires access to telecom infrastructure, such as the SS7 network, making it more associated with well-resourced actors than ordinary users.

The vulnerability may persist because older SIM cards can still contain vulnerable software, and eSIMs can also use vulnerable software. SIM software is not typically updated like a phone’s operating system.

Mitigations

The proposed protections are carrier-side:

• Filter malicious binary SMS messages.
• Disable the vulnerable applet.
• Update SIM firmware.

The video’s central takeaway is that users generally cannot fix the issue with an app or phone setting.

Source and Scope

A single narrator delivers the technical explanation and analysis, quoting unnamed security researchers on the need for carrier-side fixes. The video presents SIMjacker as a broader warning about legacy trust relationships and the separate components inside phones; it does not provide a hands-on attack guide or product review.