CVE-2021-40831 Information

Description

The AWS IoT Device SDK v2 for Java Python C++ and Node.js appends a user supplied Certificate Authority (CA) to the root CAs instead of overriding it on macOS systems. Additionally SNI validation is also not enabled when the CA has been “overridden”. TLS handshakes will thus succeed if the peer can be verified either from the user-supplied CA or the system’s default trust-store. Attackers with access to a host’s trust stores or are able to compromise a certificate authority already in the host’s trust store (note: the attacker must also be able to spoof DNS in this case) may be able to use this issue to bypass CA pinning. An attacker could then spoof the MQTT broker and either drop traffic and/or respond with the attacker’s data but they would not be able to forward this data on to the MQTT broker because the attacker would still need the user’s private keys to authenticate against the MQTT broker. The ‘aws_tls_ctx_options_override_default_trust_store_’ function within the aws-c-io submodule has been updated to address this behavior. This issue affects: Amazon Web Services AWS IoT Device SDK v2 for Java versions prior to 1.5.0 on macOS. Amazon Web Services AWS IoT Device SDK v2 for Python versions prior to 1.7.0 on macOS. Amazon Web Services AWS IoT Device SDK v2 for C++ versions prior to 1.14.0 on macOS. Amazon Web Services AWS IoT Device SDK v2 for Node.js versions prior to 1.6.0 on macOS. Amazon Web Services AWS-C-IO 0.10.7 on macOS.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Reference

https://github.com/aws/aws-iot-device-sdk-js-v2 https://github.com/awslabs/aws-c-io/ https://github.com/aws/aws-iot-device-sdk-python-v2 https://github.com/aws/aws-iot-device-sdk-cpp-v2 https://github.com/aws/aws-iot-device-sdk-java-v2

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction Required

HIGH

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.2