CVE-2017-5143 in XL Web II
Summary
by MITRE
An issue was discovered in Honeywell XL Web II controller XL1000C500 XLWebExe-2-01-00 and prior, and XLWeb 500 XLWebExe-1-02-08 and prior. A user without authenticating can make a directory traversal attack by accessing a specific URL.
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Analysis
by VulDB Data Team • 08/14/2020
The vulnerability identified as CVE-2017-5143 represents a critical security flaw in Honeywell XL Web II controllers, specifically affecting firmware versions up to XLWebExe-2-01-00 and XLWeb 500 XLWebExe-1-02-08. This issue stems from inadequate input validation within the web interface component of these industrial control systems, creating a path traversal attack vector that bypasses authentication mechanisms entirely. The flaw allows unauthenticated remote attackers to access sensitive system files and directories through carefully crafted URL requests, potentially exposing critical operational data and system configurations.
The technical implementation of this vulnerability resides in the web server component of the Honeywell controllers, where the application fails to properly sanitize user-supplied input parameters before processing file access requests. This weakness enables attackers to manipulate URL parameters to navigate through the file system hierarchy and retrieve files that should normally be restricted to authorized users only. The vulnerability specifically affects the web-based management interface, which is designed to provide remote access to controller configuration and monitoring functions, but lacks proper access controls for directory traversal operations.
From an operational perspective, this vulnerability poses significant risks to industrial control systems, as it allows attackers to gain unauthorized access to system configuration files, log data, and potentially sensitive operational parameters. The impact extends beyond simple information disclosure, as attackers could potentially manipulate system behavior by accessing or modifying critical files, leading to operational disruptions or even safety hazards in industrial environments where these controllers are deployed. The lack of authentication requirements for the directory traversal attack makes this particularly dangerous as it can be exploited remotely without any prior credentials or access rights.
The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This weakness allows attackers to access files and directories stored outside the web root folder, potentially exposing sensitive information or even system files. The ATT&CK framework categorizes this under T1083 - File and Directory Discovery, which represents techniques used to gather information about local file systems and network shares. Organizations should implement network segmentation and access controls to limit exposure, while also ensuring that all industrial control systems are kept up to date with vendor security patches and firmware updates.
Mitigation strategies should include immediate firmware updates from Honeywell to address the vulnerability, network-level restrictions to limit access to the affected web interface, and implementation of additional authentication mechanisms for any web-based access points. System administrators should also conduct thorough security assessments of their industrial control environments to identify similar vulnerabilities and ensure proper network segmentation between operational technology and corporate networks. Regular vulnerability scanning and monitoring of industrial control system components remains essential for maintaining security posture against similar threats.