CVE-2021-1757
📋 TL;DR
CVE-2021-1757 is an out-of-bounds read vulnerability in Apple operating systems that allows a local attacker to potentially elevate their privileges. This affects macOS, iOS, iPadOS, watchOS, and tvOS systems running outdated versions. Successful exploitation could lead to unauthorized access to sensitive system resources.
💻 Affected Systems
- macOS
- iOS
- iPadOS
- watchOS
- tvOS
📦 What is this software?
Ipados by Apple
Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains root/system privileges, leading to complete system compromise, data theft, and persistent backdoor installation.
Likely Case
Local user escalates privileges to gain unauthorized access to protected files, processes, or system functions.
If Mitigated
With proper patching, the vulnerability is eliminated; with network segmentation and least privilege, impact is limited to isolated systems.
🎯 Exploit Status
Requires local access and some technical knowledge to exploit. No public exploit code is known, but Apple has confirmed the vulnerability is exploitable.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4, iPadOS 14.4
Vendor Advisory: https://support.apple.com/en-us/HT212146
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update on macOS or Settings > General > Software Update on iOS/iPadOS. 2. Install the available security update. 3. Restart the device when prompted.
🔧 Temporary Workarounds
No effective workarounds
allThis is a core operating system vulnerability that requires patching. No configuration changes or workarounds are available.
🧯 If You Can't Patch
- Restrict local access to affected systems through physical security and user access controls
- Implement strict least privilege principles to limit damage from potential privilege escalation
🔍 How to Verify
Check if Vulnerable:
Check system version: On macOS, go to Apple menu > About This Mac. On iOS/iPadOS, go to Settings > General > About. Compare with patched versions listed in affected_systems.versions.Check Version:
macOS: sw_vers -productVersion; iOS/iPadOS: Settings > General > About > VersionVerify Fix Applied:
Verify system version matches or exceeds patched versions listed in fix_official.patch_version.📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation events in system logs
- Processes running with unexpected privileges
- Failed or successful authorization events from unusual sources
Network Indicators:
- No network indicators as this is local exploitation
SIEM Query:
source="apple_system_logs" AND (event_type="privilege_escalation" OR process_name="*" AND user_change="*")🔗 References
- https://support.apple.com/en-us/HT212146
- https://support.apple.com/en-us/HT212147
- https://support.apple.com/en-us/HT212148
- https://support.apple.com/en-us/HT212149
- https://support.apple.com/en-us/HT212146
- https://support.apple.com/en-us/HT212147
- https://support.apple.com/en-us/HT212148
- https://support.apple.com/en-us/HT212149
