CVE-2017-3201 in Flamingo amf-serializer
Summary
by MITRE
The Java implementation of AMF3 deserializers used in Flamingo amf-serializer by Exadel, version 2.2.0 derives class instances from java.io.Externalizable rather than the AMF3 specification's recommendation of flash.utils.IExternalizable. A remote attacker with the ability to spoof or control an RMI server connection may be able to send serialized Java objects that execute arbitrary code when deserialized.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-2017-3201 resides within the Java implementation of AMF3 deserializers used in Flamingo amf-serializer version 2.2.0 developed by Exadel. This flaw represents a critical security issue that exploits the improper handling of serialized objects during the deserialization process, creating potential attack vectors for remote code execution. The vulnerability specifically impacts systems that utilize RMI (Remote Method Invocation) connections where AMF3 serialized data is processed, making it particularly dangerous in enterprise environments where such communication patterns are common.
The technical flaw stems from the deviation from established AMF3 specification requirements in the Flamingo implementation. According to the AMF3 specification, class instances should derive from flash.utils.IExternalizable rather than java.io.Externalizable. This deviation creates a security gap because the java.io.Externalizable interface provides different serialization behavior that can be manipulated by attackers. When a remote attacker can control or spoof an RMI server connection, they can craft malicious serialized objects that exploit this implementation difference to execute arbitrary code on the target system. The vulnerability essentially allows attackers to bypass normal security boundaries during the deserialization process, transforming what should be a safe data transfer mechanism into a potential attack surface.
The operational impact of this vulnerability is severe and multifaceted. Systems utilizing Flamingo amf-serializer version 2.2.0 become susceptible to remote code execution attacks, which can lead to complete system compromise. Attackers can leverage this vulnerability to gain unauthorized access to sensitive data, escalate privileges, or establish persistent backdoors within the network. The attack vector requires only the ability to spoof or control an RMI server connection, which can be achieved through various network-level attacks or by compromising systems that communicate with vulnerable endpoints. This makes the vulnerability particularly dangerous in distributed environments where RMI connections are common and network security controls may not adequately protect against such attacks.
Mitigation strategies for CVE-2017-3201 should focus on immediate remediation through version updates of the Flamingo amf-serializer library to versions that properly implement the AMF3 specification. Organizations should also implement network segmentation and access controls to limit RMI communication paths and reduce the attack surface. Additional protective measures include implementing strict input validation for all serialized data, using application firewalls to monitor and filter suspicious RMI traffic, and conducting thorough security assessments of all systems that utilize the affected library. From a compliance perspective, this vulnerability aligns with CWE-502 which addresses deserialization of untrusted data, and it maps to ATT&CK technique T1059.007 for command and scripting interpreter. The vulnerability demonstrates the critical importance of adhering to established serialization standards and the potential consequences of deviating from specification requirements in security-sensitive implementations.