CVE Vulnerabilities

CVE-2019-19826

Deserialization of Untrusted Data

Published: Dec 16, 2019 | Modified: Dec 27, 2019
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.5 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

The Views Dynamic Fields module through 7.x-1.0-alpha4 for Drupal makes insecure unserialize calls in handlers/views_handler_filter_dynamic_fields.inc, as demonstrated by PHP object injection, involving a field_names object and an Archive_Tar object, for file deletion. Code execution might also be possible.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Views_dynamic_field Drupal * 6.x-1.4 (including)
Views_dynamic_field Drupal 7.x-1.0-alpha1 (including) 7.x-1.0-alpha1 (including)
Views_dynamic_field Drupal 7.x-1.0-alpha2 (including) 7.x-1.0-alpha2 (including)
Views_dynamic_field Drupal 7.x-1.0-alpha3 (including) 7.x-1.0-alpha3 (including)
Views_dynamic_field Drupal 7.x-1.0-alpha4 (including) 7.x-1.0-alpha4 (including)

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