CVE-2016-2166 in Qpid Proton
Summary
by MITRE
The (1) proton.reactor.Connector, (2) proton.reactor.Container, and (3) proton.utils.BlockingConnection classes in Apache Qpid Proton before 0.12.1 improperly use an unencrypted connection for an amqps URI scheme when SSL support is unavailable, which might allow man-in-the-middle attackers to obtain sensitive information or modify data via unspecified vectors.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability identified as CVE-2016-2166 affects Apache Qpid Proton versions prior to 0.12.1 and represents a critical security flaw in how the messaging library handles secure connection protocols. This issue manifests in three specific classes within the Proton library including proton.reactor.Connector, proton.reactor.Container, and proton.utils.BlockingConnection which are fundamental components for establishing and managing message broker connections. The flaw occurs when applications attempt to use the amqps URI scheme, which is specifically designed to indicate secure SSL/TLS connections, but the library fails to properly validate whether SSL support is actually available. When SSL support is missing from the runtime environment, the library incorrectly falls back to using an unencrypted connection instead of properly rejecting the secure connection attempt. This behavior creates a dangerous security boundary where the application believes it is establishing a secure connection but is actually communicating over plaintext, leaving sensitive data vulnerable to interception and modification. The vulnerability directly relates to CWE-310, which addresses cryptographic issues, specifically focusing on the improper implementation of cryptographic protocols where security mechanisms fail to provide the expected level of protection. The attack vector for this vulnerability aligns with MITRE ATT&CK technique T1046, which covers network service scanning and manipulation, as attackers can exploit this flaw to perform man-in-the-middle attacks by intercepting and modifying communications between clients and message brokers. The operational impact of this vulnerability is severe as it undermines the fundamental security assumptions of applications using Apache Qpid Proton for messaging. When SSL support is unavailable or improperly configured, the library's failure to reject secure connection attempts means that sensitive information such as authentication credentials, message payloads, and other confidential data can be exposed to unauthorized parties. The vulnerability essentially creates a false sense of security where applications appear to be using encrypted communication channels but are actually transmitting data in plaintext over the network. This flaw particularly affects distributed systems where message brokers are used for critical operations and where security compliance requirements mandate encrypted communication channels. Organizations using affected versions of Apache Qpid Proton may experience data breaches, unauthorized access to sensitive information, and potential compliance violations when this vulnerability is exploited. The implementation issue stems from inadequate validation logic that fails to properly check for SSL availability before attempting to establish connections using the amqps scheme. This type of vulnerability is classified as a security misconfiguration where the system's default behavior does not align with the security requirements of the protocol being used. The fix for CVE-2016-2166 required updating the Proton library to properly validate SSL support before attempting to establish amqps connections and to reject connection attempts when SSL is not available, rather than falling back to insecure plaintext connections. This remediation ensures that applications using the amqps URI scheme will either successfully establish secure connections or will fail gracefully with appropriate error messages indicating that secure connections cannot be established due to missing SSL support. The vulnerability demonstrates the critical importance of proper protocol enforcement and the dangers of insecure fallback behaviors in cryptographic implementations, where the failure to properly validate security prerequisites can lead to complete compromise of the security model.