CVE-2011-4512 in SIMATIC HMI panel
Summary
by MITRE
CRLF injection vulnerability in the HMI web server in Siemens WinCC flexible 2004, 2005, 2007, and 2008 before SP3; WinCC V11 (aka TIA portal) before SP2 Update 1; the TP, OP, MP, Comfort Panels, and Mobile Panels SIMATIC HMI panels; WinCC V11 Runtime Advanced; and WinCC flexible Runtime allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 11/29/2021
The CVE-2011-4512 vulnerability represents a critical cross-site scripting and HTTP response splitting flaw within Siemens HMI web servers that affects multiple generations of WinCC software and HMI panels. This vulnerability resides in the web server component of Siemens' industrial automation products, specifically targeting the WinCC flexible 2004 through 2008 versions, WinCC V11 (TIA Portal) before SP2 Update 1, and various SIMATIC HMI panels including TP, OP, MP, Comfort Panels, and Mobile Panels. The flaw allows remote attackers to manipulate HTTP headers through CRLF (Carriage Return Line Feed) injection techniques, creating a pathway for sophisticated attack vectors that can compromise the integrity of web-based industrial control systems.
The technical implementation of this vulnerability stems from inadequate input validation within the HMI web server's response handling mechanism. When user-supplied data containing CRLF sequences is processed without proper sanitization, attackers can inject malicious HTTP headers into the server's response. This CRLF injection capability enables attackers to perform HTTP response splitting attacks, where they can manipulate the HTTP response by injecting additional headers or content that gets interpreted by web browsers or intermediate proxies. The vulnerability manifests through unspecified vectors within the web server's processing of user input, making it particularly challenging to detect and prevent through conventional security measures.
The operational impact of CVE-2011-4512 extends beyond simple web-based attacks to potentially compromise entire industrial control systems. Attackers exploiting this vulnerability could redirect users to malicious websites, steal session cookies, perform man-in-the-middle attacks, or inject malicious content into web interfaces that operators use to interact with industrial processes. The affected Siemens products are commonly deployed in critical infrastructure environments where unauthorized access to HMI interfaces could lead to operational disruptions, safety hazards, or even physical damage to industrial processes. This vulnerability particularly threatens environments where HMI panels serve as primary interfaces for monitoring and controlling industrial equipment, as the injected headers could manipulate the user experience in ways that obscure or alter critical operational data.
Organizations should implement comprehensive mitigation strategies that include immediate patching of affected systems to the latest available service packs and updates from Siemens. Network segmentation and firewall rules should be configured to restrict access to HMI web servers from untrusted networks, while implementing proper input validation mechanisms at multiple layers of the network stack. The vulnerability aligns with CWE-113 (Improper Neutralization of CRLF Sequences) and represents a significant concern for industrial control system security, particularly when considering ATT&CK framework tactics such as T1190 (Exploit Public-Facing Application) and T1566 (Phishing). Regular security assessments and monitoring of web server logs for suspicious header injection patterns should be implemented as part of ongoing security operations to detect potential exploitation attempts. Given the industrial nature of affected systems, organizations should also consider the broader implications of this vulnerability on operational technology security and ensure that security measures align with industrial cybersecurity frameworks and standards.