Privacy is at the heart of Apple’s philosophy, but even the best can slip on a banana peel. On June 24, 2024, Apple released an update to patch a surprising bug – CVE-2024-44207. This vulnerability let audio messages in the Messages app record a few seconds *before* the microphone indicator (the orange dot) lit up, effectively capturing snippets unbeknownst to the user. Apple addressed this vulnerability with improved checks in iOS 18..1 and iPadOS 18..1.
This post will break down the issue in simple language, including code snippets, reference links, and what you need to know about its exploitation.
What is CVE-2024-44207?
CVE-2024-44207 is a privacy issue discovered in the Messages app in iOS and iPadOS. Specifically, it involved the way audio messages were handled: when a user tried to record an audio message, the app would begin capturing audio before the system showed the orange microphone indicator.
Impact:
A malicious actor (or simply anyone with access to your device) could leverage this to secretly listen to a few seconds of your conversation, violating your privacy expectation.
Severity:
Medium – Your phone wasn’t continuously recording, but a few unnotified seconds could still expose sensitive words or sounds.
User opens Messages and taps the microphone to record an audio message.
2. System microphone activates, but for a brief moment, the orange privacy indicator *does not* show – even though recording has started.
3. A few seconds of audio are recorded *before* the user is visually alerted that the microphone is live.
4. Potential for misuse: An attacker or mischievous actor could exploit this by tricking someone into recording an audio message when they weren’t prepared, catching off-guard responses.
Technical Details
No public proof-of-concept exploit has been released due to the privacy nature of the bug and Apple’s responsible disclosure practices, but let’s imagine what the problematic flow could look like, using pseudocode inspired by the relevant iOS APIs.
Pseudocode of the Vulnerable Sequence
// Simplified & hypothetical example
func beginAudioMessageRecording() {
// Step 1: Prepare audio session, NOT YET showing indicator
AudioSession.prepare()
// Step 2: Start recording audio right away
AudioRecorder.start() // <-- Audio is being captured here!
// Step 3: Update UI (delayed orange dot, etc.)
showMicrophoneIndicator() // <-- Only now does the user see they are being recorded
}
Issue:
AudioRecorder.start() is called *before* showMicrophoneIndicator(). This led to a window where recording was happening, but the indicator wasn’t on screen.
Audio isn’t captured *until* the system has confirmed the indicator is visible.
- They added extra checks to prevent recording from starting even a millisecond before the indicator.
Hypothetical Fixed Flow
func beginAudioMessageRecordingSecurely() {
// Step 1: Prepare and show the indicator FIRST
showMicrophoneIndicator()
// Step 2: Wait for the system to confirm indicator is live
await systemConfirmsIndicator()
// Step 3: Only then start recording
AudioRecorder.start() // Now recording, and the user is 100% warned
}
Is This a Real-World Concern?
Yes, but mostly for those who are privacy-focused. While most people wouldn’t notice a 2-3 second recording window, the expectation is absolute: when Apple says the dot means “your mic is recording,” anything before that is a breach of trust.
Apple Security Update (June 24, 2024):
About iOS 18..1 and iPadOS 18..1 Security Content
NVD Entry:
Apple’s Official Description:
> "Audio messages in Messages may be able to capture a few seconds of audio before the microphone indicator is activated. This issue was addressed with improved checks."
Timeline
Published on: 10/04/2024 00:15:02 UTC
Last modified on: 10/04/2024 17:31:41 UTC