CVE-2017-14942 in WRN 150
Summary
by MITRE
Intelbras WRN 150 devices allow remote attackers to read the configuration file, and consequently bypass authentication, via a direct request for cgi-bin/DownloadCfg/RouterCfm.cfg containing an admin:language=pt cookie.
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Analysis
by VulDB Data Team • 11/24/2019
The vulnerability identified as CVE-2017-14942 affects Intelbras WRN 150 wireless routers, representing a critical security flaw that enables remote attackers to bypass authentication mechanisms through direct manipulation of web requests. This issue stems from improper access controls within the device's web interface implementation, specifically in how it handles configuration file access. The vulnerability is classified under CWE-284 Access Control Issues, which encompasses problems where systems fail to properly enforce access restrictions on resources. The affected device exposes sensitive configuration files through a predictable URI path structure that allows unauthorized users to retrieve administrative settings without proper authentication.
The technical exploitation of this vulnerability occurs through a straightforward yet effective method involving crafted HTTP requests that target the specific configuration file path cgi-bin/DownloadCfg/RouterCfm.cfg. Attackers can bypass authentication by simply including a specific cookie value in their request, namely admin:language=pt, which appears to be a language preference parameter that inadvertently grants access to sensitive configuration data. This flaw demonstrates poor input validation and inadequate session management, as the device does not properly verify the legitimacy of requests before serving privileged content. The vulnerability is particularly concerning because it allows attackers to obtain complete router configuration files, which typically contain sensitive information such as administrative credentials, network settings, and potentially other confidential data.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with comprehensive knowledge of the router's configuration and potentially allows for further exploitation. Once an attacker gains access to the configuration file, they can extract administrative credentials, network topology information, and other sensitive data that could be used for additional attacks within the network. This vulnerability directly impacts the CIA triad by compromising confidentiality and integrity, as unauthorized parties can access sensitive configuration data and potentially modify it. The attack vector is particularly dangerous because it requires no specialized tools or complex exploitation techniques, making it accessible to even novice attackers. This vulnerability aligns with ATT&CK technique T1213 Data from Information Repositories, as it involves extracting configuration data from network devices, and T1078 Valid Accounts, since the attacker can potentially use extracted credentials for further access.
Mitigation strategies for this vulnerability should focus on implementing proper access controls and input validation mechanisms within the device's web interface. Network administrators should immediately update firmware to versions that address this specific flaw, as Intelbras likely released patches to fix the improper access control issue. Additionally, implementing network segmentation and access control lists can help limit exposure of these devices to unauthorized networks. The solution should include proper authentication checks before serving any configuration files, ensuring that only authenticated administrative users can access sensitive data. Organizations should also consider implementing network monitoring to detect suspicious requests targeting configuration file paths and establish regular security assessments to identify similar access control flaws in other network devices. The vulnerability highlights the importance of proper security testing and validation of web application components, particularly in embedded systems where resource constraints may lead to inadequate security implementations.