CVE Vulnerabilities

CVE-2021-31010

Deserialization of Untrusted Data

Published: Aug 24, 2021 | Modified: Nov 07, 2023
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu

A deserialization issue was addressed through improved validation. This issue is fixed in Security Update 2021-005 Catalina, iOS 12.5.5, iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6, watchOS 7.6.2. A sandboxed process may be able to circumvent sandbox restrictions. Apple was aware of a report that this issue may have been actively exploited at the time of release..

Weakness

The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.

Affected Software

Name Vendor Start Version End Version
Ipados Apple * 14.8 (excluding)
Iphone_os Apple 12.0 (including) 12.5.5 (excluding)
Iphone_os Apple 14.0 (including) 14.8 (excluding)
Mac_os_x Apple 10.15 (including) 10.15.7 (excluding)
Mac_os_x Apple 10.15.7 (including) 10.15.7 (including)
Mac_os_x Apple 10.15.7-security_update_2020 (including) 10.15.7-security_update_2020 (including)
Mac_os_x Apple 10.15.7-security_update_2020-001 (including) 10.15.7-security_update_2020-001 (including)
Mac_os_x Apple 10.15.7-security_update_2020-005 (including) 10.15.7-security_update_2020-005 (including)
Mac_os_x Apple 10.15.7-security_update_2020-007 (including) 10.15.7-security_update_2020-007 (including)
Mac_os_x Apple 10.15.7-security_update_2021-001 (including) 10.15.7-security_update_2021-001 (including)
Mac_os_x Apple 10.15.7-security_update_2021-002 (including) 10.15.7-security_update_2021-002 (including)
Mac_os_x Apple 10.15.7-security_update_2021-003 (including) 10.15.7-security_update_2021-003 (including)
Mac_os_x Apple 10.15.7-security_update_2021-006 (including) 10.15.7-security_update_2021-006 (including)
Mac_os_x Apple 10.15.7-security_update_2021-007 (including) 10.15.7-security_update_2021-007 (including)
Mac_os_x Apple 10.15.7-security_update_2021-008 (including) 10.15.7-security_update_2021-008 (including)
Mac_os_x Apple 10.15.7-security_update_2022-001 (including) 10.15.7-security_update_2022-001 (including)
Mac_os_x Apple 10.15.7-security_update_2022-002 (including) 10.15.7-security_update_2022-002 (including)
Mac_os_x Apple 10.15.7-security_update_2022-003 (including) 10.15.7-security_update_2022-003 (including)
Mac_os_x Apple 10.15.7-security_update_2022-004 (including) 10.15.7-security_update_2022-004 (including)
Mac_os_x Apple 10.15.7-supplemental_update (including) 10.15.7-supplemental_update (including)
Macos Apple 11.0 (including) 11.6 (excluding)
Watchos Apple * 7.6.2 (excluding)

Extended Description

It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security – which is a dangerous security assumption. Data that is untrusted can not be trusted to be well-formed. When developers place no restrictions on “gadget chains,” or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.

Potential Mitigations

  • Make fields transient to protect them from deserialization.
  • An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

References