CVE-2013-4261 in OpenStack
Summary
by MITRE
OpenStack Compute (Nova) Folsom, Grizzly, and earlier, when using Apache Qpid for the RPC backend, does not properly handle errors that occur during messaging, which allows remote attackers to cause a denial of service (connection pool consumption), as demonstrated using multiple requests that send long strings to an instance console and retrieving the console log.
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Analysis
by VulDB Data Team • 01/10/2022
The vulnerability identified as CVE-2013-4261 affects OpenStack Compute (Nova) versions Folsom through Grizzly and specifically impacts systems utilizing Apache Qpid as the Remote Procedure Call (RPC) backend. This flaw represents a critical security weakness that stems from improper error handling mechanisms within the messaging infrastructure, creating a pathway for remote attackers to exploit the system's connection management capabilities. The vulnerability manifests when the system fails to adequately process error conditions that occur during message transmission, leading to a cascading effect that consumes available connection resources within the pool.
The technical implementation of this vulnerability involves the interaction between Nova's RPC layer and Apache Qpid's messaging system, where error conditions during message processing are not properly sanitized or handled. When attackers send multiple requests containing excessively long strings to instance consoles and subsequently retrieve console logs, the system's connection pool becomes progressively consumed without proper cleanup or resource management. This behavior directly violates the principles outlined in CWE-400, which addresses unchecked resource consumption, and demonstrates how inadequate error handling can lead to resource exhaustion attacks. The flaw operates at the intersection of distributed computing and resource management, where the messaging system's inability to properly terminate or recycle connections creates a persistent vulnerability.
From an operational perspective, this vulnerability enables remote attackers to execute a denial of service attack that specifically targets the connection pool resources within the OpenStack Nova environment. The attack pattern involves sending multiple malformed requests with long strings that trigger error conditions in the Qpid messaging layer, causing connections to remain open or improperly closed. This consumption of connection pool resources effectively prevents legitimate users from establishing new connections to the Nova services, creating a service disruption that impacts the entire cloud infrastructure. The attack can be executed without requiring authentication credentials, making it particularly dangerous as it can be launched from any external network location. This aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion.
The impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall availability and reliability of cloud computing services. When the connection pool becomes exhausted, legitimate users experience connection failures and service unavailability, which can cascade throughout the OpenStack environment and affect multiple virtual machine instances. The vulnerability's exploitation demonstrates a fundamental weakness in the system's resource management architecture, where error conditions are not properly isolated and handled, leading to resource leakage that can be systematically exploited. Organizations using affected OpenStack versions face significant operational risks, including potential service outages that can affect business continuity and customer satisfaction. The vulnerability also highlights the importance of proper error handling and resource management in distributed systems, particularly those handling high volumes of concurrent connections. Security practitioners should note that this issue represents a classic example of how seemingly minor implementation flaws in messaging systems can lead to major availability concerns. The proper mitigation requires updating to patched versions of OpenStack Nova or implementing connection pool management controls that limit resource consumption and ensure proper cleanup of failed connections.