CVE Vulnerabilities

CVE-2020-3280

Deserialization of Untrusted Data

Published: May 22, 2020 | Modified: May 27, 2020
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
10 HIGH
AV:N/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

A vulnerability in the Java Remote Management Interface of Cisco Unified Contact Center Express (Unified CCX) could allow an unauthenticated, remote attacker to execute arbitrary code on an affected device. The vulnerability is due to insecure deserialization of user-supplied content by the affected software. An attacker could exploit this vulnerability by sending a malicious serialized Java object to a specific listener on an affected system. A successful exploit could allow the attacker to execute arbitrary code as the root user on an affected device.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Unified_contact_center_express Cisco 12.0 (including) 12.0(1)es03 (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