CVE-2023-35921 in SIMATIC
Summary
by MITRE • 07/11/2023
A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3.4), SIMATIC MV540 S (All versions < V3.3.4), SIMATIC MV550 H (All versions < V3.3.4), SIMATIC MV550 S (All versions < V3.3.4), SIMATIC MV560 U (All versions < V3.3.4), SIMATIC MV560 X (All versions < V3.3.4). Affected devices cannot properly process specially crafted Ethernet frames sent to the devices. This could allow an unauthenticated remote attacker to cause a denial of service condition. The affected devices must be restarted manually.
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Analysis
by VulDB Data Team • 07/11/2023
This vulnerability affects Siemens industrial automation devices including MV540 H, MV540 S, MV550 H, MV550 S, MV560 U, and MV560 X models across multiple software versions. The flaw resides in the network protocol processing capabilities of these devices, specifically in how they handle incoming Ethernet frames. The vulnerability represents a classic buffer over-read or malformed packet processing issue that allows an attacker to craft specially designed network traffic that the devices cannot properly handle.
The technical implementation of this vulnerability involves the devices' failure to properly validate or sanitize incoming Ethernet frames before processing them. When these malformed frames are received, the affected systems experience abnormal behavior that leads to system instability and ultimately results in a denial of service condition. This type of vulnerability falls under CWE-129, which describes improper validation of input boundaries, and aligns with ATT&CK technique T1498.001 for Denial of Service through resource exhaustion or system instability. The devices require manual restart to recover from this condition, indicating that the system does not have automatic recovery mechanisms in place.
The operational impact of this vulnerability extends beyond simple service disruption as it affects industrial control systems that typically operate in critical infrastructure environments. These devices are commonly used in manufacturing, process control, and industrial automation applications where availability is paramount. The remote nature of the attack means that an unauthenticated attacker can potentially disrupt operations from external networks without requiring physical access or credentials. This vulnerability creates a significant risk for industrial environments where continuous operation is critical and where the cost of downtime can be substantial. The need for manual restart operations further compounds the impact as it requires on-site personnel or remote access procedures to restore service, potentially delaying recovery times.
Mitigation strategies should include immediate firmware updates to versions 3.3.4 or later where the vulnerability has been addressed. Network segmentation and access controls should be implemented to limit exposure to untrusted networks and reduce the attack surface. Monitoring network traffic for suspicious Ethernet frame patterns can help detect potential exploitation attempts. Organizations should also implement robust incident response procedures that include manual restart capabilities and backup recovery processes. The vulnerability demonstrates the importance of maintaining up-to-date industrial control system firmware and following security best practices for critical infrastructure environments. Regular security assessments and vulnerability scanning of industrial networks should be conducted to identify and remediate similar issues before they can be exploited in operational environments.