CVE-2018-1298 in Qpid Broker-J
Summary
by MITRE
A Denial of Service vulnerability was found in Apache Qpid Broker-J 7.0.0 in functionality for authentication of connections for AMQP protocols 0-8, 0-9, 0-91 and 0-10 when PLAIN or XOAUTH2 SASL mechanism is used. The vulnerability allows unauthenticated attacker to crash the broker instance. AMQP 1.0 and HTTP connections are not affected. An authentication of incoming AMQP connections in Apache Qpid Broker-J is performed by special entities called "Authentication Providers". Each Authentication Provider can support several SASL mechanisms which are offered to the connecting clients as part of SASL negotiation process. The client chooses the most appropriate SASL mechanism for authentication. Authentication Providers of following types supports PLAIN SASL mechanism: Plain, PlainPasswordFile, SimpleLDAP, Base64MD5PasswordFile, MD5, SCRAM-SHA-256, SCRAM-SHA-1. XOAUTH2 SASL mechanism is supported by Authentication Providers of type OAuth2. If an AMQP port is configured with any of these Authentication Providers, the Broker may be vulnerable.
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Analysis
by VulDB Data Team • 01/03/2020
The vulnerability described in CVE-2018-1298 represents a critical denial of service weakness within Apache Qpid Broker-J version 7.0.0 that specifically targets the authentication mechanisms used for AMQP protocol connections. This flaw affects the broker's handling of authentication providers when utilizing PLAIN or XOAUTH2 SASL mechanisms, creating a scenario where unauthenticated attackers can deliberately crash the broker instance. The vulnerability is particularly significant because it undermines the fundamental security posture of the messaging system, allowing remote attackers to disrupt service availability without requiring any valid credentials or authentication. The affected protocols include AMQP versions 0-8, 0-9, 0-91, and 0-10, while AMQP 1.0 and HTTP connections remain unaffected, indicating a protocol-specific scope of impact. This vulnerability directly relates to CWE-400, which encompasses weaknesses that enable denial of service attacks through resource exhaustion or system instability, and aligns with ATT&CK technique T1499.001 for network denial of service attacks. The authentication process in Apache Qpid Broker-J relies on specialized entities known as Authentication Providers that manage the SASL negotiation process, where clients select appropriate authentication mechanisms from those offered by the server. When an AMQP port is configured with specific authentication providers that support PLAIN or XOAUTH2 mechanisms, the system becomes vulnerable to this particular attack vector. The affected authentication providers include Plain, PlainPasswordFile, SimpleLDAP, Base64MD5PasswordFile, MD5, SCRAM-SHA-256, SCRAM-SHA-1 for PLAIN mechanism, and OAuth2 for XOAUTH2 mechanism, creating multiple potential entry points for exploitation. The operational impact of this vulnerability extends beyond simple service disruption, as it represents a complete system compromise where an attacker can render the entire messaging infrastructure unavailable. This type of vulnerability is particularly dangerous in production environments where message brokers serve as critical infrastructure components, as it can lead to cascading failures throughout dependent systems that rely on message queuing for communication. The attack requires minimal prerequisites since it targets unauthenticated connections, making it accessible to any attacker who can establish network connectivity to the affected AMQP ports. Security practitioners should note that the vulnerability's exploitation does not require authentication credentials, which means that even unauthorized access attempts can trigger the denial of service condition, effectively creating a low-barrier attack surface that can be exploited by malicious actors or automated scanning tools. The root cause of this vulnerability stems from inadequate input validation and error handling within the authentication provider implementations, specifically when processing malformed or maliciously crafted SASL negotiation sequences. This weakness allows attackers to craft specific connection attempts that cause the broker to enter an unstable state or crash entirely. The vulnerability's classification under CWE-400 emphasizes the importance of robust error handling and resource management in security-critical components, while its alignment with ATT&CK techniques highlights the need for monitoring and defensive measures against such denial of service attacks. Organizations should prioritize immediate patching of affected Apache Qpid Broker-J installations and implement network segmentation to limit exposure of AMQP ports to untrusted networks. Additionally, monitoring for unusual authentication patterns and connection attempts should be implemented to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation in authentication systems and serves as a reminder that even seemingly benign authentication mechanisms can become attack vectors when not properly secured against malformed input sequences.