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

• Spring AMQP
  • 1.0.0 to 2.4.16
  • 3.0.0 to 3.0.9

• 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

This vulnerability was responsibly reported by L0ne1y.