CVE Vulnerabilities

CVE-2019-6338

Deserialization of Untrusted Data

Published: Jan 22, 2019 | Modified: Nov 07, 2023
CVSS 3.x
8
HIGH
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
CVSS 2.x
6 MEDIUM
AV:N/AC:M/Au:S/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM

In Drupal Core versions 7.x prior to 7.62, 8.6.x prior to 8.6.6 and 8.5.x prior to 8.5.9; Drupal core uses the third-party PEAR Archive_Tar library. This library has released a security update which impacts some Drupal configurations. Refer to CVE-2018-1000888 for details

Weakness

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

Affected Software

Name Vendor Start Version End Version
Drupal Drupal 7.0 (including) 7.62 (excluding)
Drupal Drupal 8.5.0 (including) 8.5.9 (excluding)
Drupal Drupal 8.6.0 (including) 8.6.6 (excluding)
Drupal7 Ubuntu esm-apps/xenial *
Drupal7 Ubuntu esm-infra-legacy/trusty *
Drupal7 Ubuntu trusty *
Drupal7 Ubuntu trusty/esm *
Drupal7 Ubuntu xenial *

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