CVE-2018-13815 in SIMATIC S7-1200
Summary
by MITRE
A vulnerability has been identified in SIMATIC S7-1200 (All versions), SIMATIC S7-1500 (All Versions < V2.6). An attacker could exhaust the available connection pool of an affected device by opening a sufficient number of connections to the device. Successful exploitation requires an attacker to be able to send packets to port 102/tcp of the affected device. No user interaction and no user privileges are required to exploit the vulnerability. The vulnerability, if exploited, could cause a Denial-of-Service condition impacting the availability of the system. At the time of advisory publication no public exploitation of this vulnerability was known.
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Analysis
by VulDB Data Team • 06/18/2023
This vulnerability affects Siemens SIMATIC S7-1200 and S7-1500 programmable logic controllers where an attacker can perform a denial-of-service attack by exhausting the device's connection pool through excessive connection attempts to port 102/tcp. The issue stems from insufficient connection management mechanisms within the industrial control system's communication stack, allowing unauthorized entities to consume all available connection slots without proper authentication or resource limiting. The vulnerability exists in all versions of S7-1200 and S7-1500 devices below version 2.6, making a significant portion of industrial automation infrastructure potentially susceptible to this type of attack. The root cause aligns with CWE-400, specifically CWE-400: Uncontrolled Resource Consumption, which occurs when a system fails to properly manage or limit resource allocation, leading to resource exhaustion. This flaw represents a classic resource exhaustion attack vector that targets the fundamental connection handling mechanisms of industrial control systems.
The operational impact of this vulnerability extends beyond simple service disruption as it can compromise the availability of critical industrial processes that rely on these controllers for automation and control functions. When the connection pool is exhausted, legitimate users or processes attempting to establish connections to the device will be unable to communicate with the controller, potentially leading to production halts, safety system failures, or process control disruptions in manufacturing environments. The attack requires no user interaction or privileges, making it particularly dangerous as it can be executed remotely by any entity capable of sending packets to the target device's port 102. This characteristic places the vulnerability within the ATT&CK framework's T1499.004 category, specifically targeting availability through resource exhaustion attacks, and demonstrates how industrial control systems can be targeted through network-based attacks that exploit fundamental protocol implementation flaws.
Mitigation strategies for this vulnerability should focus on implementing network segmentation and access control measures to restrict access to port 102/tcp from unauthorized networks. Organizations should deploy firewalls and access control lists to limit which systems can communicate with the affected devices on the designated port, effectively reducing the attack surface. Additionally, implementing connection rate limiting and monitoring mechanisms can help detect and prevent excessive connection attempts that may indicate an ongoing attack. The most effective long-term solution involves upgrading affected devices to versions 2.6 or later where Siemens has addressed the connection pool management issue through improved resource allocation and connection handling mechanisms. Network administrators should also establish monitoring protocols to track connection attempts and implement intrusion detection systems that can identify unusual connection patterns that may indicate resource exhaustion attempts. The vulnerability highlights the importance of industrial cybersecurity practices and proper network architecture design in protecting critical infrastructure from denial-of-service attacks that target fundamental system resources.