CVE-2011-4529 in Automation License Manager
Summary
by MITRE
Multiple buffer overflows in Siemens Automation License Manager (ALM) 4.0 through 5.1+SP1+Upd1 allow remote attackers to execute arbitrary code via a long serialid field in an _licensekey command, as demonstrated by the (1) check_licensekey or (2) read_licensekey command.
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Analysis
by VulDB Data Team • 04/06/2025
The vulnerability identified as CVE-2011-4529 represents a critical buffer overflow flaw within Siemens Automation License Manager software versions 4.0 through 5.1+SP1+Upd1. This issue stems from inadequate input validation mechanisms that fail to properly handle excessively long serialid parameters within the _licensekey command structure. The affected system components process license verification requests through specific command handlers that do not implement proper bounds checking on incoming data fields, creating exploitable conditions that can be leveraged by remote attackers to gain unauthorized system access.
The technical implementation of this vulnerability manifests through the improper handling of the serialid field parameter in license key operations. When the system receives a malformed _licensekey command containing an excessively long serialid value, the buffer allocation fails to account for the overflow condition, causing adjacent memory regions to be overwritten. This memory corruption typically occurs during the processing of either the check_licensekey or read_licensekey commands, where the application's string handling functions do not validate the length of incoming serialid data before attempting to store or process it within fixed-size memory buffers. The flaw aligns with CWE-121, which categorizes buffer overflow conditions occurring in stack-based buffers, and represents a classic example of unsafe string manipulation practices.
Operationally, this vulnerability presents significant security implications for industrial control systems and automation environments that rely on Siemens ALM for license management. Remote attackers can exploit this weakness from any network location to execute arbitrary code with the privileges of the affected application process, potentially leading to complete system compromise. The attack vector requires only the ability to send specially crafted license key commands to the target system, making it particularly dangerous in environments where network access to automation systems is not properly restricted. The vulnerability's impact extends beyond simple code execution to potentially enable privilege escalation attacks and persistent backdoor establishment, as demonstrated by various threat actor campaigns targeting industrial control systems.
The exploitation of this vulnerability typically follows a pattern where attackers craft malicious license key commands with oversized serialid fields, sending them to the target ALM service. The resulting buffer overflow can overwrite critical program execution data including return addresses, function pointers, or other control flow information, allowing attackers to redirect program execution to malicious code payloads. This type of attack aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution and T1078.004 for valid accounts, as the exploitation may require legitimate administrative access to properly construct and send the malicious commands. Organizations using affected Siemens ALM versions should implement immediate mitigations including network segmentation, access control restrictions, and application-level input validation measures to reduce the attack surface and protect against potential exploitation attempts.
The remediation approach for this vulnerability requires immediate software patching from Siemens to address the buffer overflow conditions in the license management functionality. System administrators should also implement network monitoring to detect suspicious license key command patterns and establish strict access controls around the affected ALM services. Additionally, organizations should conduct comprehensive vulnerability assessments to identify other potentially affected systems and ensure proper input validation controls are implemented across all license management and authentication components. The vulnerability demonstrates the critical importance of proper input validation in industrial control systems where network exposure and remote attack vectors can lead to significant operational disruptions and security breaches.