CVE-2011-4877 in SIMATIC HMI panel
Summary
by MITRE
HmiLoad in the runtime loader in Siemens WinCC flexible 2004, 2005, 2007, and 2008; WinCC V11 (aka TIA portal); the TP, OP, MP, Comfort Panels, and Mobile Panels SIMATIC HMI panels; WinCC V11 Runtime Advanced; and WinCC flexible Runtime, when Transfer Mode is enabled, allows remote attackers to cause a denial of service (application crash) by sending crafted data over TCP.
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Analysis
by VulDB Data Team • 04/08/2025
The vulnerability identified as CVE-2011-4877 represents a critical denial of service weakness affecting Siemens HMI (Human Machine Interface) products within the WinCC flexible and WinCC V11 ecosystems. This flaw exists in the HmiLoad component of the runtime loader across multiple Siemens products including various versions of WinCC flexible 2004, 2005, 2007, and 2008, as well as the TIA portal version 11, encompassing TP, OP, MP, Comfort Panels, and Mobile Panels SIMATIC HMI panels alongside WinCC V11 Runtime Advanced and WinCC flexible Runtime. The vulnerability specifically manifests when Transfer Mode is enabled, creating an exploitable condition that allows remote attackers to disrupt system operations through carefully crafted TCP data transmission.
The technical mechanism underlying this vulnerability involves improper input validation within the HmiLoad runtime loader component. When Transfer Mode is active, the system processes incoming TCP data without adequate sanitization or bounds checking, allowing maliciously constructed data packets to trigger memory corruption or resource exhaustion conditions. This flaw falls under the CWE-121 category of Stack-based Buffer Overflow, where the system fails to properly validate data length and content before processing, leading to potential application crashes or system instability. The vulnerability is particularly concerning because it operates at the runtime loader level, meaning it can affect the core operational functionality of HMI panels during normal execution.
The operational impact of CVE-2011-4877 extends beyond simple service disruption, potentially compromising industrial control system integrity and operational continuity. In industrial environments where Siemens HMI panels are deployed for process control and monitoring, a successful exploitation could result in unauthorized system downtime, production halts, and potential safety risks. The remote nature of the attack means that threat actors can target these systems from external networks without requiring physical access, making the vulnerability particularly dangerous in connected industrial environments. This weakness directly relates to ATT&CK technique T1499.004 for Network Denial of Service, where adversaries leverage system vulnerabilities to disrupt operational capabilities.
Mitigation strategies for this vulnerability should focus on immediate network segmentation and access control measures to prevent unauthorized remote access to affected HMI systems. Organizations should disable Transfer Mode on affected systems when not actively required for configuration updates, as this removes the attack vector entirely. Network firewalls should be configured to restrict TCP access to HMI panels to trusted administrative networks only, implementing strict ingress and egress filtering rules. Additionally, regular security updates and patches from Siemens should be applied immediately upon availability, as the vendor likely provided remediation for this specific vulnerability. System monitoring should include detection of unusual TCP traffic patterns and application crash events that may indicate exploitation attempts, while also implementing network intrusion detection systems to identify potential attack signatures targeting this specific vulnerability.