Description

In 2016, allowed list patterns for deserializable class names were added to Spring AMQP, allowing users to lock down deserialization of data in messages from untrusted sources; however by default, when no allowed list was provided, all classes could be deserialized.

Specifically, and application is vulnerable if

the SimpleMessageConverter or SerializerMessageConverter is used
the user does not configure allowed list patterns
untrusted message originators gain permissions to write messages to the RabbitMQ broker to send malicious content

Affected Spring Products and Versions

Spring AMQP
- 1.0.0 to 2.4.16
- 3.0.0 to 3.0.9

Mitigation

Do not allow untrusted sources to access the RabbitMQ server
Users with versions less that 2.4.17 should upgrade to 2.4.17
Users using versions 3.0.0 to 3.0.9 should upgrade to 3.0.10

Spring Boot dependency management will pull in the corrected versions, starting with Boot versions 2.7.17, 3.0.12, 3.1.5, and 3.2.0.

Allowed class name patterns are now required.

However, users who wish to revert to the previous behavior of trusting all, can set a global environment property or system property; refer to the Java Deserialization documentation section