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March 14, 2025
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How to Protect Your SiPass Integrated Systems from CVE-2025-27494?
Siemens SiPass integrated systems are widely used for access control in various organizations. Recently, a critical vulnerability, CVE-2025-27494, has been discovered in these systems, posing a significant security risk. This vulnerability allows authenticated remote administrators to execute arbitrary commands with root privileges, potentially leading to complete system compromise. This article provides security professionals with a detailed understanding of the vulnerability, its impact, and, most importantly, the steps needed to mitigate and remediate the flaw, ensuring the safety and integrity of their SiPass integrated systems.
A Short Introduction to SiPass Integrated Systems
SiPass integrated is an access control and security management system developed by Siemens. It provides a comprehensive solution for managing access to buildings, facilities, and other secured areas. The system typically includes hardware components like door controllers, readers, and locks, as well as software for managing user access rights, monitoring events, and generating reports. SiPass integrated AC5102 (ACC-G2) and ACC-AP are central controller devices in the SiPass integrated system. They manage and control access points, user credentials, and system configurations. The REST API in these devices is used for remote administration and integration with other systems.
Summary of CVE-2025-27494
CVE ID: CVE-2025-27494
Description: Improper input sanitization for the REST API's pubkey endpoint allows authenticated remote administrators to perform command injection attacks.
CVSS Score: 9.4 (Critical)
CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CVE-2025-27494 is a critical vulnerability that arises from the failure to properly sanitize user-supplied input to the pubkey endpoint of the REST API. This vulnerability specifically affects SiPass integrated AC5102 (ACC-G2) and SiPass integrated ACC-AP devices. An authenticated remote administrator with high privileges can exploit this flaw by injecting arbitrary commands that are then executed with root privileges on the system. The improper input validation allows attackers to bypass security mechanisms and directly inject malicious commands into the system.
Impact of CVE-2025-27494
The impact of CVE-2025-27494 is severe. Successful exploitation can lead to a complete compromise of the affected SiPass integrated systems. An attacker with root-level access can perform a variety of malicious activities:
Unauthorized Access: Gain unrestricted access to secured areas.
Data Theft: Steal sensitive information, including user credentials and access logs.
System Manipulation: Modify system configurations, potentially disabling security features.
Denial of Service: Disrupt critical access control infrastructure, preventing authorized personnel from entering secured areas.
Lateral Movement: Use the compromised system as a pivot point to attack other systems on the network.
Given the critical nature of access control systems, a successful attack can have far-reaching consequences, including physical security breaches, operational disruptions, and financial losses. Organizations must, therefore, prioritize the remediation of this vulnerability to protect their assets and ensure the safety of their personnel. You should know what is a vulnerability.
Products Affected by CVE-2025-27494
The following products and versions are affected by CVE-2025-27494:
| Product | Affected Versions | Fixed Versions |
|---|---|---|
| SiPass integrated AC5102 (ACC-G2) | All versions < V6.4.9 | V6.4.9 and above |
| SiPass integrated ACC-AP | All versions < V6.4.9 | V6.4.9 and above |
It is important to note that only versions prior to V6.4.9 are vulnerable. Upgrading to V6.4.9 or later will remediate the vulnerability. There are no explicitly listed non-affected products in the advisory, but it is safe to assume that any product not listed is not affected. You can read the security advisories for more details.
How to Check Your Product is Vulnerable?
To determine if your SiPass integrated system is vulnerable to CVE-2025-27494, follow these steps:
Access the System: Log in to the SiPass integrated AC5102 (ACC-G2) or ACC-AP device through its web interface or command-line interface (CLI).
Check the Firmware Version: Navigate to the system information or about section to identify the installed firmware version.
Compare with Affected Versions: Compare the installed version with the list of affected versions provided in the "Products Affected by CVE-2025-27494" section. If the version is earlier than V6.4.9, the system is vulnerable.
REST API Endpoint Verification (Advanced): You can attempt to send a crafted request to the
/pubkeyendpoint of the REST API. However, this requires a deep understanding of the API and the vulnerability. This approach is not recommended for those without the necessary expertise. Instead, focus on upgrading to the fixed version.Log Analysis (If Available): Check system logs for suspicious REST API activities. Look for unusual patterns or error messages related to the
/pubkeyendpoint. Note that this approach is only useful for detecting potential exploitation attempts, not for identifying the presence of the vulnerability itself.
How to Fix the Vulnerability?
The primary remediation strategy for CVE-2025-27494 is to upgrade the affected SiPass integrated systems to version V6.4.9 or later. Here's a detailed guide:
Upgrade to V6.4.9 or Later:
Download the latest version of the SiPass integrated software from the official Siemens website or authorized channels.
Follow the upgrade instructions provided by Siemens. Ensure you back up your system configuration before initiating the upgrade process.
After the upgrade, verify that the system is running version V6.4.9 or later.
Workarounds and Mitigations (If Immediate Upgrade is Not Possible):
Restrict and Monitor Administrator REST API Access: Limit access to the REST API to only trusted administrators and monitor their activities closely.
Implement Network Segmentation: Isolate the SiPass integrated systems on a separate network segment to limit the potential impact of a successful attack.
Use Strong Authentication Mechanisms: Enforce strong passwords for all administrator accounts and consider implementing multi-factor authentication (MFA) if available. To implement this you should know what is authentication bypass.
Apply the Principle of Least Privilege: Grant administrator accounts only the necessary privileges to perform their tasks.
Monitor System Logs for Suspicious REST API Activities: Regularly review system logs for any unusual or unauthorized activity related to the REST API.
Set an individual strong password for the administrator account ("SIEMENS")
Note: If there is no specific mention of an available patch or the patch is not released yet, ask users to monitor official channels for any security updates or patch management related to this vulnerability.
By following these steps, security professionals can effectively mitigate the risk posed by CVE-2025-27494 and protect their SiPass integrated systems from potential exploitation. Regular vulnerability assessments and proactive patching are crucial for maintaining a secure access control infrastructure.
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Arun KL
Arun KL is a cybersecurity professional with 15+ years of experience in IT infrastructure, cloud security, vulnerability management, Penetration Testing, security operations, and incident response. He is adept at designing and implementing robust security solutions to safeguard systems and data. Arun holds multiple industry certifications including CCNA, CCNA Security, RHCE, CEH, and AWS Security.
