CVE-2018-14713 in RT-AC3200
Summary
by MITRE
Format string vulnerability in appGet.cgi on ASUS RT-AC3200 version 3.0.0.4.382.50010 allows attackers to read arbitrary sections of memory and CPU registers via the "hook" URL parameter.
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Analysis
by VulDB Data Team • 09/15/2023
The vulnerability identified as CVE-2018-14713 represents a critical format string vulnerability located within the appGet.cgi component of ASUS RT-AC3200 firmware version 3.0.0.4.382.50010. This flaw exists in the web interface handling mechanism where the application fails to properly sanitize user input before using it in format string functions. The specific entry point for exploitation occurs through the "hook" URL parameter, which is processed without adequate validation or sanitization measures. This vulnerability falls under the category of CWE-134, which specifically addresses the use of format strings with user-controlled data, making it a well-documented weakness in software security practices.
The technical implementation of this vulnerability allows remote attackers to manipulate the format string parsing functionality by injecting specially crafted payloads through the hook parameter. When the application processes this parameter, it directly passes the user-supplied input to functions like printf or sprintf without proper formatting controls. This misconfiguration enables attackers to construct format specifiers that can trigger memory read operations, potentially exposing sensitive information stored in memory segments including CPU registers, stack contents, and other internal application data. The vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication, making it accessible to any attacker who can reach the device's web interface.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with significant insight into the device's internal memory structure and potentially sensitive data. An attacker could leverage this vulnerability to discover memory addresses, application stack contents, and other confidential information that could be used for further exploitation attempts. The exposure of CPU registers and memory sections creates opportunities for advanced attack vectors including privilege escalation, memory corruption exploitation, or crafting more sophisticated attacks against the device's firmware. This vulnerability essentially provides a window into the device's operational memory space, which can significantly aid in developing subsequent attack strategies against the affected router.
Security mitigations for CVE-2018-14713 should focus on implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in format string operations. The firmware should be updated to ensure that all user input is properly escaped or filtered before being used in printf-like functions. Additionally, implementing proper access controls and input length restrictions for the hook parameter can prevent exploitation attempts. Organizations should also consider network segmentation and monitoring to detect anomalous traffic patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as it allows for arbitrary code execution through memory disclosure, and represents a classic example of improper input validation that violates security best practices outlined in various industry standards including NIST SP 800-160 and ISO/IEC 27001. Regular firmware updates and security assessments should be implemented to prevent similar vulnerabilities from being introduced in future versions of the device's software stack.