CVE-2023-34050 in Spring AMQP
Summary
by MITRE • 10/25/2023
In spring AMQP versions 1.0.0 to 2.4.16 and 3.0.0 to 3.0.9 , 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, an 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
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Analysis
by VulDB Data Team • 11/11/2023
The vulnerability described in CVE-2023-34050 represents a critical deserialization flaw within Spring AMQP versions ranging from 1.0.0 through 2.4.16 and 3.0.0 through 3.0.9. This issue stems from the implementation of allowed list patterns for deserializable class names, which were introduced as a security measure to restrict deserialization of data from untrusted sources. However, the default configuration behavior created a dangerous security gap where applications would permit deserialization of all classes when no explicit allowed list was configured. The vulnerability specifically impacts applications utilizing either the SimpleMessageConverter or SerializerMessageConverter components, which are fundamental to message processing within the Spring AMQP framework. When these converters operate without proper security configuration, they become susceptible to malicious deserialization attacks that can execute arbitrary code on the target system.
The technical flaw manifests in the default security configuration of Spring AMQP's message conversion mechanisms, creating a dangerous default state where no restrictions exist on deserialization operations. This vulnerability operates under the principle that when no explicit allowed list patterns are provided, the system defaults to permitting deserialization of all classes, which directly violates secure coding practices and security by design principles. The flaw aligns with CWE-502, which specifically addresses deserialization of untrusted data as a critical security weakness. When an application employs the SimpleMessageConverter or SerializerMessageConverter without proper allowed list configuration, any malicious actor who gains the ability to write messages to the RabbitMQ broker can exploit this vulnerability by crafting specially designed malicious message content that, upon deserialization, executes arbitrary code on the target system. This represents a classic remote code execution vulnerability that can be exploited from the network level.
The operational impact of CVE-2023-34050 is severe and far-reaching for organizations utilizing Spring AMQP in their messaging infrastructure. Attackers can leverage this vulnerability to gain complete control over affected systems, potentially leading to data breaches, system compromise, and further lateral movement within network environments. The vulnerability is particularly dangerous because it requires minimal privileges to exploit - only the ability to write messages to the RabbitMQ broker, which is often more accessible than direct system access. Organizations using Spring AMQP in production environments face significant risk of unauthorized access and potential system compromise. The vulnerability affects the core messaging functionality of Spring applications, making it particularly impactful for distributed systems that rely heavily on message-based communication patterns. The attack surface is broad since RabbitMQ is commonly used in enterprise environments, and the default insecure configuration means that many applications are vulnerable without explicit security hardening.
Mitigation strategies for CVE-2023-34050 require immediate configuration changes to establish proper allowed list patterns for deserializable classes. Organizations should implement explicit allowed list configurations using the available Spring AMQP security features to restrict which classes can be deserialized from messages. The recommended approach involves configuring specific patterns that permit only known safe classes to be deserialized, following the principle of least privilege. Security teams should conduct comprehensive audits of their Spring AMQP configurations to identify all applications using the vulnerable converters and ensure proper allowed list patterns are implemented. Additionally, organizations should consider upgrading to patched versions of Spring AMQP where available, as this vulnerability has been addressed in subsequent releases. The implementation of these mitigations should align with ATT&CK technique T1203, which focuses on legitimate user privileges for privilege escalation, by ensuring that message processing components operate with minimal necessary permissions. Regular security testing and monitoring of message queues should be implemented to detect any potential exploitation attempts, and organizations should establish security policies that mandate proper configuration of deserialization security settings for all messaging components.