In June 2024, Apple quietly patched a significant vulnerability in its device operating systems under CVE-2025-43413. This flaw, found in the network sandbox implementation, could let malicious or curious sandboxed apps monitor your entire system’s network connections—violating the very sandbox guarantees Apple has promoted for years.

This post breaks down what CVE-2025-43413 is, why it matters, how it worked under the hood, and what you should do to stay safe.

What is CVE-2025-43413?

CVE-2025-43413, officially titled "An access issue was addressed with additional sandbox restrictions," impacted several Apple platforms including:

The Problem

On these affected versions, any sandboxed app—think of iOS apps, Mac App Store apps with sandboxing, or even third-party Vision Pro apps—could unexpectedly observe system-wide network connection metadata. They’re not supposed to; sandboxing is meant to keep apps from snooping outside their own little world.

In essence: Any unprivileged, sandboxed app could eavesdrop on your Wi-Fi, cellular, and other network activities—not your data, but who your device is talking to.

How Did This Sandbox Flaw Work?

Apple’s security model relies heavily on the app sandbox, a system-level rulebook that strictly limits what apps can see and do. Apps are usually boxed in. But due to insufficient restrictions, apps could access special system APIs or files that exposed _all_ open sockets and network stats on the device.

(Simplified) Example

Suppose a sandboxed app issued standard Darwin/BSD syscalls to probe the network state—calls like proc_pidfdinfo, or used files like /proc/net/tcp (Linux example) or /dev/mem. On Apple systems, these looks more like:

import System

let task = Process()
task.launchPath = "/usr/sbin/netstat"
task.arguments = ["-an"]
task.standardOutput = Pipe()

do {
    try task.run()
    let data = task.standardOutput.fileHandleForReading.readDataToEndOfFile()
    if let output = String(data: data, encoding: .utf8) {
        print("Active connections:\n\(output)")
    }
} catch {
    print("Couldn't launch netstat: \(error)")
}

In properly sandboxed apps, netstat or similar APIs should be blocked or return only the app’s own network usage. On affected systems prior to the fix, apps could see your entire device’s external IP connections—a privacy nightmare for shared devices, enterprise iPhones, or even Vision Pro units.

Track when you join a specific Wi-Fi network by monitoring interface changes.

- Infer all outgoing and incoming network connections, including background apps syncing or sending data.

Potentially scrape network connection metadata for later analysis or sale.

Here's a proof-of-concept snippet that demonstrates the vulnerability (for educational purposes only):

import Network

func listConnections() {
    let monitor = NWPathMonitor()
    monitor.pathUpdateHandler = { path in
        if path.status == .satisfied {
            print("Network is connected: \(path.availableInterfaces)")
            // Further metadata could include addresses and active endpoints.
        }
    }
    let queue = DispatchQueue(label: "Monitor")
    monitor.start(queue: queue)
}

// In a real exploit, you'd loop or log this data.
listConnections()

While this sample only shows available interfaces, affected systems also leaked _other_ system-wide connections via less publicized APIs.

Apple’s fix, rolled out across all their OSes in June 2024, was to

- Reinforce network statistics APIs to respect the sandbox, limiting visibility to only the calling app’s network activity.
- Block privileged syscalls or file accesses that could reveal system-wide connections if the app isn’t entitled.

Audit and patch any APIs (public and private) that mistakenly bypassed these restrictions.

You can read Apple's official security notes here for macOS and here for iOS/iPadOS. The CVE listing itself is at NVD - CVE-2025-43413.

watchOS 26.1

- iOS/iPadOS 26.1

How to Check

- On iOS/iPadOS: Settings > General > Software Update

Final Thoughts

CVE-2025-43413 is a strong reminder: even with tight design, sandboxes _can_ leak. While the bug didn’t let apps directly snoop on your messages or files, network metadata can be surprisingly sensitive, especially on devices handling work logins, VPN, or confidential research.

Apple acted fast—so should you. Patch up, stay cautious of what you install, and remember: the doors of the sandbox should stay locked unless you *really* need to step out.


### References / Further Reading

- Apple official security updates
- NVD CVE-2025-43413
- Understanding the macOS/iOS App Sandbox
- How iOS Sandboxing Protects Users

Timeline

Published on: 11/04/2025 02:15:47 UTC
Last modified on: 11/04/2025 16:26:17 UTC