CVE-2021-40359 : Exploit Details and Defense Strategies

A vulnerability has been identified in OpenPCS 7, SIMATIC BATCH, SIMATIC NET PC Software, SIMATIC PCS 7, SIMATIC Route Control, and SIMATIC WinCC products by Siemens that could allow an attacker to read unexpected critical files.

Understanding CVE-2021-40359

This CVE record outlines a potential path traversal vulnerability affecting multiple Siemens products.

What is CVE-2021-40359?

The CVE-2021-40359 vulnerability pertains to the failure of affected systems to properly neutralize special elements within the pathname while downloading files. Exploiting this flaw may lead to the resolution of the pathname to a location outside the restricted directory, enabling unauthorized access to critical files.

The Impact of CVE-2021-40359

If successfully exploited, this vulnerability could result in an attacker being able to read critical files from the server that were not meant to be accessed, posing a significant security risk to the affected systems.

Technical Details of CVE-2021-40359

This section provides in-depth technical insights into the vulnerability.

Vulnerability Description

The vulnerability involves a lack of proper neutralization of special elements within pathnames during file downloads, allowing attackers to access files outside the intended directory.

Affected Systems and Versions

The following Siemens products and versions are known to be affected by CVE-2021-40359:

OpenPCS 7 V8.2 (All versions)
OpenPCS 7 V9.0 (All versions < V9.0 Upd4)
OpenPCS 7 V9.1 (All versions)
SIMATIC BATCH V8.2 (All versions)
SIMATIC BATCH V9.0 (All versions)
SIMATIC BATCH V9.1 (All versions)
SIMATIC NET PC Software V14 (All versions)
SIMATIC NET PC Software V15 (All versions)
SIMATIC NET PC Software V16 (All versions < V16 Update 6)
SIMATIC NET PC Software V17 (All versions < V17 SP1)
SIMATIC PCS 7 V8.2 (All versions)
SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04)
SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1)
SIMATIC Route Control V8.2 (All versions)
SIMATIC Route Control V9.0 (All versions)
SIMATIC Route Control V9.1 (All versions)
SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7)
SIMATIC WinCC V16 (All versions < V16 Update 5)
SIMATIC WinCC V17 (All versions < V17 Update 2)
SIMATIC WinCC V7.4 (All versions < V7.4 SP1 Update 19)
SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 5)

Exploitation Mechanism

Exploiting the vulnerability involves manipulating elements within a pathname during file download to access files residing outside the expected directory.

Mitigation and Prevention

Proactive measures are essential to mitigate the risks associated with CVE-2021-40359.

Immediate Steps to Take

To address this vulnerability, users are advised to:

Apply patches provided by Siemens once available.
Implement network segmentation to limit the impact of a potential attack.
Monitor network traffic for any suspicious activity indicating a possible exploitation attempt.

Long-Term Security Practices

In the long run, organizations can enhance their security posture by:

Conducting regular security audits and assessments to identify vulnerabilities.
Educating users and administrators about secure file management practices.
Utilizing robust access control policies to restrict unauthorized file access.

Patching and Updates

Stay informed about security updates released by Siemens for the affected products and apply patches promptly to safeguard systems against potential exploitation.