CVE-2017-12734 in LOGO!
Summary
by MITRE
A vulnerability has been identified in Siemens LOGO! devices before V1.81.2. An attacker with network access to the integrated web server on port 80/tcp could obtain the session ID of an active user session. A user must be logged in to the web interface. Siemens recommends to use the integrated webserver on port 80/tcp only in trusted networks.
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Analysis
by VulDB Data Team • 12/27/2022
This vulnerability affects Siemens LOGO! devices running firmware versions prior to V1.81.2 and represents a significant session management flaw that undermines the security of the device's web interface. The issue stems from improper session ID generation or handling within the integrated web server component that operates on port 80/tcp, allowing remote attackers to extract active session identifiers from authenticated user sessions. The vulnerability requires network access to the device's web server and assumes that a legitimate user has already established an authenticated session, which creates a specific attack vector that leverages session hijacking techniques. This weakness directly violates fundamental security principles of session management and authentication mechanisms that should protect user sessions from unauthorized access.
The technical implementation flaw manifests as insufficient entropy or predictable session ID generation within the web server component, enabling attackers to capture valid session tokens through network traffic analysis or other reconnaissance methods. Once an attacker obtains a valid session ID, they can impersonate the authenticated user and gain unauthorized access to the device's web interface, potentially leading to complete device compromise. The vulnerability's impact is amplified by the fact that it operates at the application layer, making it accessible through standard network protocols without requiring physical access or specialized equipment. This type of vulnerability aligns with CWE-384, which addresses session management weaknesses that allow session hijacking attacks, and represents a clear violation of the principle of least privilege in access control mechanisms.
The operational implications of this vulnerability extend beyond simple unauthorized access, as it enables attackers to manipulate device configurations, view sensitive operational data, and potentially disrupt industrial control processes that rely on these devices. The integrated web server on port 80/tcp serves as a primary interface for device management, making this vulnerability particularly dangerous in industrial environments where LOGO! devices control critical processes. Attackers could leverage this weakness to modify device settings, disable security features, or create persistent backdoors within the network infrastructure. The risk is further compounded by the fact that many industrial environments lack proper network segmentation, making devices accessible from untrusted networks where such attacks could be executed without significant difficulty.
Siemens' recommended mitigation strategy of restricting web server usage to trusted networks represents a pragmatic approach to addressing this vulnerability while acknowledging the device's operational constraints. However, this recommendation only partially addresses the underlying security issue and does not provide a permanent fix for devices that must operate in untrusted network environments. Organizations should implement additional security controls including network segmentation, firewall rules limiting access to port 80/tcp, and regular firmware updates to ensure devices receive the necessary security patches. The vulnerability demonstrates the importance of secure session management practices and highlights the need for proper security testing of industrial control systems. This issue aligns with ATT&CK technique T1566 which covers credential access through session hijacking and manipulation, emphasizing the need for robust authentication and session management in industrial control systems.