CVE-2023-26151 in asyncua
Summary
by MITRE • 10/25/2023
Versions of the package asyncua before 0.9.96 are vulnerable to Denial of Service (DoS) such that an attacker can send a malformed packet and as a result, the server will enter into an infinite loop and consume excessive memory.
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Analysis
by VulDB Data Team • 10/25/2023
The CVE-2023-26151 vulnerability affects the asyncua package, a popular python implementation of the OPC UA (Open Platform Communications Unified Architecture) protocol used extensively in industrial automation and IoT systems. This vulnerability represents a critical denial of service weakness that can be exploited by remote attackers to disrupt the operation of OPC UA servers. The asyncua package serves as a client and server implementation for OPC UA communication, making it essential for connecting industrial devices and systems in manufacturing, energy, and other critical infrastructure sectors. The vulnerability specifically impacts versions prior to 0.9.96, indicating that organizations using older releases of this package face significant operational risks.
The technical flaw manifests when the asyncua server receives a malformed packet that triggers an infinite loop in the processing logic. This particular weakness occurs during the handling of certain OPC UA protocol messages where the server fails to properly validate incoming data structures or implement adequate input sanitization measures. The malformed packet exploits a condition where the server enters a continuous processing cycle without proper termination conditions, leading to unbounded resource consumption. This type of vulnerability falls under the category of resource exhaustion attacks where the attacker can consume system memory and CPU cycles indefinitely, effectively rendering the service unavailable to legitimate users.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire industrial control systems. When an OPC UA server becomes unresponsive due to the infinite loop, it can lead to cascading failures in automated processes that depend on real-time communication between devices and control systems. The memory consumption aspect of this vulnerability is particularly concerning as it can cause the server to crash or become unresponsive, potentially resulting in production downtime and safety risks in industrial environments. Organizations using asyncua in critical infrastructure contexts face the risk of operational disruption that could affect manufacturing processes, energy grid management, or other essential services.
Organizations should immediately upgrade to asyncua version 0.9.96 or later to remediate this vulnerability, as no reliable workarounds exist for the specific infinite loop condition. The fix implemented in version 0.9.96 addresses the packet validation logic and adds proper input sanitization to prevent malformed packets from triggering the problematic code path. Security teams should also implement network-level monitoring to detect unusual memory consumption patterns or repeated connection attempts that might indicate exploitation attempts. This vulnerability aligns with CWE-400, which covers "Uncontrolled Resource Consumption" and relates to ATT&CK technique T1499.004 for "Endpoint Denial of Service" within the context of industrial control systems. Organizations should also consider implementing network segmentation and access controls to limit exposure of OPC UA servers to untrusted networks, as the vulnerability can be exploited remotely without authentication requirements.