A race condition was addressed with improved locking. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. A malicious application may be able to elevate privileges. Apple is aware of a report that this issue may have been actively exploited..
Weakness
The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ipados | Apple | * | 14.4 (excluding) |
| Iphone_os | Apple | * | 14.4 (excluding) |
| Mac_os_x | Apple | 10.14 (including) | 10.14.6 (excluding) |
| Mac_os_x | Apple | 10.15 (including) | 10.15.7 (excluding) |
| Mac_os_x | Apple | 10.14.6 (including) | 10.14.6 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2019-004 (including) | 10.14.6-security_update_2019-004 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2019-005 (including) | 10.14.6-security_update_2019-005 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2019-006 (including) | 10.14.6-security_update_2019-006 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2019-007 (including) | 10.14.6-security_update_2019-007 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-001 (including) | 10.14.6-security_update_2020-001 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-002 (including) | 10.14.6-security_update_2020-002 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-003 (including) | 10.14.6-security_update_2020-003 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-004 (including) | 10.14.6-security_update_2020-004 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-005 (including) | 10.14.6-security_update_2020-005 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-006 (including) | 10.14.6-security_update_2020-006 (including) |
| Mac_os_x | Apple | 10.14.6-security_update_2020-007 (including) | 10.14.6-security_update_2020-007 (including) |
| Mac_os_x | Apple | 10.14.6-supplemental_update (including) | 10.14.6-supplemental_update (including) |
| Mac_os_x | Apple | 10.14.6-supplemental_update_2 (including) | 10.14.6-supplemental_update_2 (including) |
| Mac_os_x | Apple | 10.15.7 (including) | 10.15.7 (including) |
| Mac_os_x | Apple | 10.15.7-supplemental_update (including) | 10.15.7-supplemental_update (including) |
| Macos | Apple | 11.0 (including) | 11.2 (excluding) |
| Tvos | Apple | * | 14.4 (excluding) |
| Watchos | Apple | * | 7.3 (excluding) |
Extended Description
Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.
Potential Mitigations
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/25.html
- https://cwe.mitre.org/data/definitions/26.html
- https://cwe.mitre.org/data/definitions/27.html
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
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1782