In early 2022, Apple patched a noteworthy vulnerability—CVE-2022-22583—that allowed malicious applications to peek into files they shouldn't have been able to see on macOS. Let's break down what this bug was, how a simple permissions mismatch could lead to a data leak, what fixes Apple made, and how attackers might have exploited it. All code and insights here are explained in clear, simple terms.

What Is CVE-2022-22583?

CVE-2022-22583 is a vulnerability that existed in macOS Catalina, Big Sur, and Monterey versions before early 2022. The issue boiled down to permissions validation, or rather, a lack of strict checking about which apps could access restricted files.  

In plain terms:  
> Malicious applications could sneakily access files reserved for processes or users with higher privileges.

macOS Big Sur 11.6.3

Apple's official advisory:  
https://support.apple.com/en-us/HT213092

How the Vulnerability Happened

macOS uses App Sandbox technology to wall off apps and prevent them from reading or manipulating files they shouldn't. But in this case, a certain API (left unnamed in advisories but documented by security researchers) failed to honor those sandbox boundaries.

Result?  
If an application called this API in a certain way, it could poke into protected directories—like another user’s files, or system settings libraries.

Let’s say a broken function looked like this before the patch

// Hypothetical vulnerable implementation

- (NSData *)readRestrictedFile:(NSString *)filePath {
    if ([self appHasReadPermission:filePath]) {
        // Mistakenly only checks standard permissions, not sandbox context or ACLs
        NSData *fileData = [NSData dataWithContentsOfFile:filePath];
        return fileData;
    } else {
        return nil;
    }
}

After the patch, Apple’s validation became more robust

- (NSData *)readRestrictedFile:(NSString *)filePath {
    if ([self appHasReadPermission:filePath] && [self isWithinSandbox:filePath]) {
        NSData *fileData = [NSData dataWithContentsOfFile:filePath];
        return fileData;
    } else {
        // Optionally log or report a violation
        return nil;
    }
}

Now, both normal permission checks and sandbox constraints are enforced.

A malicious app could

1. Get a user to download and run a seemingly harmless application (bypassing Gatekeeper or abusing user trust).

Silently scan for sensitive files, such as

- Documents from other users (/Users/otheruser/Documents/...)

Proof of Concept (Pseudo-code)

let fileManager = FileManager.default
let targetPath = "/Users/admin/Library/Keychains/login.keychain-db"

if fileManager.isReadableFile(atPath: targetPath) {
    let contents = try? Data(contentsOf: URL(fileURLWithPath: targetPath))
    // Exfiltrate data, save, or process as desired
}


  - In a securely sandboxed environment, this would fail. Due to CVE-2022-22583, it could succeed if run through the vulnerable API.

Real-World Risks

Potential impact:

How Was It Fixed?

Apple’s fix involved tightening validation in how certain APIs and system services determined file access rights:

Now, both file system permissions and App Sandbox rules are checked.

- The affected APIs perform improved validation—ensuring even a root-level process can’t bypass sandboxing where it’s meant to apply.

Upgrade Guidance:

Learn More

- Apple Security Update Advisory
- National Vulnerability Database Entry
- Mac Security Research Blog - Analysis *(example - for similar Mac bugs)*
- Apple on App Sandbox

Conclusion

CVE-2022-22583 reminds us that permission checks on modern OSes need to be layered and robust, not just based on file system attributes but also on app-origin and sandbox rules. Apple’s rapid patching averted possible widespread data leaks.

Bottom line:  
Keep your macOS up to date. Even “small” permission bugs can have huge consequences.

Timeline

Published on: 03/18/2022 18:15:00 UTC
Last modified on: 03/28/2022 15:39:00 UTC