CVE-2018-4844 in SIMATIC WinCC
Summary
by MITRE
A vulnerability has been identified in SIMATIC WinCC OA UI for Android (All versions < V3.15.10), SIMATIC WinCC OA UI for iOS (All versions < V3.15.10). Insufficient limitation of CONTROL script capabilities could allow read and write access from one HMI project cache folder to other HMI project cache folders within the app's sandbox on the same mobile device. This includes HMI project cache folders of other configured WinCC OA servers. The security vulnerability could be exploited by an attacker who tricks an app user to connect to an attacker-controlled WinCC OA server. Successful exploitation requires user interaction and read/write access to the app's folder on a mobile device. The vulnerability could allow reading data from and writing data to the app's folder. At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.
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Analysis
by VulDB Data Team • 02/22/2023
This vulnerability affects Siemens SIMATIC WinCC OA UI applications for mobile platforms, specifically targeting Android and iOS versions prior to V3.15.10. The flaw resides in the insufficient limitation of control script capabilities within the application's sandbox environment, creating a critical security gap that allows unauthorized cross-project access. The vulnerability stems from improper isolation mechanisms between different HMI project cache folders, enabling malicious actors to gain unauthorized read and write access to data belonging to other HMI projects stored within the same application sandbox. This represents a classic sandbox escape scenario where the security boundaries designed to protect individual project data have been compromised.
The technical implementation of this vulnerability involves the control script execution environment failing to properly enforce access controls between different project cache directories. When users connect to various WinCC OA servers, the application's folder structure does not adequately separate the cache data associated with each project, creating a scenario where one project's cached data can be accessed by another project's scripts. This cross-contamination occurs within the mobile device's application sandbox, which should normally provide isolation between different application instances or project contexts. The vulnerability specifically impacts the HMI project cache folders, which contain sensitive operational data, configuration information, and potentially proprietary process control parameters.
From an operational standpoint, this vulnerability presents a significant risk to industrial control system security, particularly in environments where multiple WinCC OA servers are managed on the same mobile device. Attackers can exploit this weakness by tricking users into connecting to maliciously configured WinCC OA servers, leveraging the user interaction requirement to establish the attack vector. The successful exploitation allows attackers to read sensitive data from other HMI project cache folders and potentially write malicious content that could disrupt operations or exfiltrate critical process information. This cross-project data access capability could enable attackers to gather intelligence about different industrial processes, potentially leading to targeted attacks against specific operational areas. The vulnerability's impact extends beyond simple data access, as it could facilitate more sophisticated attacks including configuration manipulation and operational disruption.
The security implications of this vulnerability align with CWE-276, which addresses improper privileges and access control issues in software applications. This weakness directly relates to inadequate sandboxing mechanisms and insufficient access control enforcement within mobile applications. The vulnerability also maps to ATT&CK technique T1059.007 for script execution and T1074.001 for data staging, as attackers could use the compromised access to execute malicious scripts and move data between different project contexts. Organizations should immediately implement the mitigations provided by Siemens, including updating to version V3.15.10 or later, which addresses the insufficient limitation of control script capabilities. Additional protective measures include implementing network segmentation to prevent unauthorized server connections, educating users about the risks of connecting to untrusted servers, and monitoring for unusual application behavior that might indicate exploitation attempts. The vulnerability highlights the critical importance of proper sandbox isolation in mobile applications handling industrial control data, particularly in environments where multiple operational contexts must be maintained securely.