CVE-2018-11459 in SINUMERIK 828D
Summary
by MITRE
A vulnerability has been identified in SINUMERIK 808D V4.7 (All versions), SINUMERIK 808D V4.8 (All versions), SINUMERIK 828D V4.7 (All versions < V4.7 SP6 HF1), SINUMERIK 840D sl V4.7 (All versions < V4.7 SP6 HF5), SINUMERIK 840D sl V4.8 (All versions < V4.8 SP3). A local attacker could modify a user-writeable configuration file so that after reboot or manual initiation the system reloads the modified configuration file and attacker-controlled code is executed with elevated privileges. The security vulnerability could be exploited by an attacker with local access to the affected system. Successful exploitation requires user privileges but no user interaction. The vulnerability could allow an attacker to compromise confidentiality, integrity and availability of the system. At the time of advisory publication no public exploitation of this security vulnerability was known.
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Analysis
by VulDB Data Team • 06/18/2023
This vulnerability affects Siemens SINUMERIK industrial control systems including models 808D and 840D series across multiple software versions. The flaw represents a critical privilege escalation vulnerability that allows local attackers to execute arbitrary code with elevated privileges. The vulnerability stems from improper handling of configuration files that are writable by regular users, creating a path for persistent code execution that survives system reboots. This type of vulnerability falls under CWE-276 which specifically addresses improper privileges and access control issues in software systems.
The technical mechanism involves an attacker modifying a user-accessible configuration file that gets reloaded during system initialization or manual restart processes. When the system restarts, it loads the modified configuration which contains attacker-controlled code that executes with elevated privileges. This creates a persistent backdoor that can compromise the entire system. The vulnerability is classified as a local privilege escalation attack since it requires physical or local access to the system but does not need user interaction or elevated privileges to begin exploitation. This aligns with ATT&CK technique T1068 which covers local privilege escalation through improper file permissions and configuration management.
The operational impact of this vulnerability is severe as it provides attackers with complete control over industrial control systems that manage critical manufacturing processes. The compromise affects both confidentiality and integrity of system operations, potentially allowing attackers to modify production parameters, access sensitive operational data, or disrupt manufacturing workflows. Availability is also at risk as attackers could potentially cause system crashes or disable critical manufacturing functions. The vulnerability affects multiple Siemens industrial control platforms, making it particularly dangerous in environments where these systems operate alongside other industrial equipment. The fact that no public exploitation was known at the time of advisory publication does not diminish the severity, as the potential for exploitation exists whenever local access is gained.
Organizations should implement immediate mitigations including restricting write permissions on configuration files, applying available vendor patches and updates, and conducting thorough access control reviews. System administrators should also implement monitoring for unauthorized modifications to critical system files and establish regular integrity checks to detect potential exploitation attempts. The vulnerability highlights the importance of secure configuration management in industrial control systems and demonstrates the need for proper privilege separation between user and system configuration files. Given the industrial control environment, additional considerations should include maintaining air-gapped networks where possible and implementing robust change management processes for configuration updates.