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                             CERT-Renater

                  Note d'Information No. 2023/VULN263

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DATE                : 24/08/2023

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running Spring for Apache Kafka versions
                                 prior to 2.9.11, 3.0.10.

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https://spring.io/security/cve-2023-34040/
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CVE-2023-34040: Java Deserialization vulnerability in Spring-Kafka
When Improperly Configured

MEDIUM | AUGUST 23, 2023 | CVE-2023-34040
Description

In Spring for Apache Kafka 3.0.9 and earlier and versions 2.9.10
and earlier, a possible deserialization attack vector existed, but
only if unusual configuration was applied. An attacker would have
to construct a malicious serialized object in one of the
deserialization exception record headers.

Specifically, an application is vulnerable when all of the following
are true:

     The user does not configure an ErrorHandlingDeserializer for the
key and/or value of the record
     The user explicitly sets container properties
checkDeserExWhenKeyNull and/or checkDeserExWhenValueNull container
properties to true.
     The user allows untrusted sources to publish to a Kafka topic

By default, these properties are false, and the container only
attempts to deserialize the headers if an ErrorHandlingDeserializer
is configured. The ErrorHandlingDeserializer prevents the
vulnerability by removing any such malicious headers before
processing the record.


Affected Spring Products and Versions

     Spring for Apache Kafka
         2.8.1 to 2.9.10
         3.0.0 to 3.0.9


Mitigation

     Do not set container properties checkDeserExWhenKeyNull or
checkDeserExWhenValueNull when not using ErrorHandlingDeserializers,
or use ErrorHandlingDeserializers


     2.8.x and 2.9.x users should upgrade to 2.9.11
     3.0.x users should upgrade to 3.0.10


Releases that have fixed this issue include:

     Spring for Apache Kafka
         3.0.10
         2.9.11

Spring boot 3.0.10 (or later) dependency management will automatically
use Spring for Apache Kafka 3.0.10 (or later). Spring Boot 2.7.x users
should override Boot's Spring for Apache Kafka 2.8.x dependency
management version to 2.9.11 (or later).


Credit

This issue was identified and responsibly reported by Joseph Beeton
from Contrast Security, Inc.


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