CVE-2023-37551 in Control
Summary
by MITRE • 08/03/2023
In multiple Codesys products in multiple versions, after successful authentication as a user, specially crafted network communication requests can utilize the CmpApp component to download files with any file extensions to the controller. In contrast to the regular file download via CmpFileTransfer, no filtering of certain file types is performed here. As a result, the integrity of the CODESYS control runtime system may be compromised by the files loaded onto the controller.
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Analysis
by VulDB Data Team • 08/26/2023
The vulnerability identified as CVE-2023-37551 represents a critical security flaw within multiple CODESYS products that directly impacts the integrity of industrial control systems. This vulnerability specifically affects the CmpApp component within the CODESYS runtime environment, creating an unauthorized file download mechanism that bypasses normal security controls. The flaw exists in the network communication handling process where authenticated users can exploit a design oversight to download arbitrary files to the controller without proper validation or filtering mechanisms. This issue is particularly concerning in industrial environments where CODESYS controllers are deployed for critical infrastructure operations, as it provides an attack vector that could lead to complete system compromise.
The technical implementation of this vulnerability stems from insufficient input validation within the CmpApp component's file handling functionality. Unlike the standard CmpFileTransfer mechanism which enforces file type restrictions and validation, the CmpApp component lacks proper filtering controls that would normally prevent the download of potentially malicious file extensions. This design flaw allows attackers to craft specially formatted network requests that can bypass the normal file type checking procedures. The vulnerability manifests when an authenticated user sends a crafted request to the controller, enabling the download of files with any extension directly to the controller's file system. This behavior creates a path for arbitrary code execution and system compromise through the installation of malicious files that can manipulate the controller's runtime environment.
The operational impact of this vulnerability extends beyond simple unauthorized file transfers, as it fundamentally compromises the integrity of the CODESYS control runtime system. When malicious files are downloaded to the controller, they can potentially overwrite critical system components, install backdoors, or introduce rootkits that persist across system reboots. The vulnerability's severity is amplified by the fact that it requires only successful authentication, which in many industrial environments may be relatively easy to achieve through credential theft, brute force attacks, or social engineering tactics. This access level allows attackers to perform operations that would normally require administrative privileges within the controller environment. The compromised system integrity can lead to complete control over industrial processes, potentially causing production disruptions, safety hazards, or even physical damage to equipment.
Mitigation strategies for CVE-2023-37551 should focus on both immediate defensive measures and long-term architectural improvements. Organizations should implement network segmentation and access controls to limit exposure of CODESYS controllers to untrusted networks, ensuring that only authorized personnel can access the system. The deployment of network monitoring solutions capable of detecting anomalous file transfer patterns and unusual network requests can provide early warning of exploitation attempts. Additionally, applying vendor-provided patches and updates as soon as they become available is critical for addressing the root cause of the vulnerability. Security professionals should also consider implementing file integrity monitoring solutions that can detect unauthorized modifications to critical system files. From a compliance perspective, this vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-73 (External Control of File Name or Path) classifications, and represents a significant concern under the ATT&CK framework's TA0003 (Persistence) and TA0004 (Privilege Escalation) tactics. Organizations should conduct comprehensive security assessments of their CODESYS implementations and ensure that proper access controls and network segmentation are in place to prevent unauthorized access to controller systems.