CVE-2017-14948 in DIR-880L
Summary
by MITRE
Certain D-Link products are affected by: Buffer Overflow. This affects DIR-880L 1.08B04 and DIR-895 L/R 1.13b03. The impact is: execute arbitrary code (remote). The component is: htdocs/fileaccess.cgi. The attack vector is: A crafted HTTP request handled by fileacces.cgi could allow an attacker to mount a ROP attack: if the HTTP header field CONTENT_TYPE starts with ''boundary=' followed by more than 256 characters, a buffer overflow would be triggered, potentially causing code execution.
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Analysis
by VulDB Data Team • 01/08/2024
The vulnerability identified as CVE-2017-14948 represents a critical buffer overflow flaw affecting specific D-Link networking devices including the DIR-880L version 1.08B04 and DIR-895 L/R version 1.13b03. This security weakness resides within the web interface component of these devices, specifically in the htdocs/fileaccess.cgi script that processes incoming HTTP requests. The flaw stems from inadequate input validation of the CONTENT_TYPE HTTP header field, creating an exploitable condition that allows remote code execution. According to CWE-121, this vulnerability falls under the category of stack-based buffer overflow, where insufficient bounds checking permits data to overwrite adjacent memory locations. The attack vector specifically targets the handling of HTTP requests processed by the fileaccess.cgi component, making it particularly dangerous as it can be exploited remotely without requiring physical access to the device. The vulnerability is particularly concerning because it enables attackers to execute arbitrary code on the affected devices, potentially compromising the entire network infrastructure.
The technical implementation of this vulnerability involves a specific condition where the CONTENT_TYPE header field must begin with the string "boundary=" followed by more than 256 characters. When this condition is met, the device's web server fails to properly validate the length of the boundary parameter, allowing an attacker to overflow a fixed-size buffer allocated on the stack. This buffer overflow creates an opportunity for attackers to manipulate the program execution flow through Return Oriented Programming (ROP) attacks, which are sophisticated exploitation techniques that chain together existing code snippets to achieve malicious objectives. The ROP attack capability significantly increases the exploit's effectiveness as it allows attackers to bypass modern security protections like stack canaries and address space layout randomization. The attack requires only a single crafted HTTP request to be sent to the vulnerable device, making it particularly easy to exploit and potentially affecting numerous devices in a network environment.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can lead to complete compromise of the affected network devices and potentially the entire network infrastructure. Attackers exploiting this vulnerability could gain persistent access to network resources, install backdoors, modify network configurations, or use the compromised devices as launch points for further attacks against other systems. The vulnerability affects enterprise and consumer networking equipment, making it particularly dangerous in environments where network security is paramount. According to ATT&CK framework, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) techniques, as successful exploitation would enable attackers to execute malicious commands and potentially escalate privileges within the compromised network. The long-term implications include potential data breaches, network infiltration, and unauthorized access to sensitive network resources that could remain undetected for extended periods.
Mitigation strategies for CVE-2017-14948 should prioritize immediate firmware updates from D-Link to address the buffer overflow condition in the affected fileaccess.cgi component. Network administrators should implement network segmentation and access controls to limit exposure of these devices to untrusted networks, while also monitoring for suspicious HTTP traffic patterns that might indicate exploitation attempts. The implementation of web application firewalls and intrusion detection systems can provide additional layers of protection by filtering malicious HTTP requests before they reach the vulnerable web interface. Regular security audits and vulnerability assessments should be conducted to identify other potentially vulnerable network devices within the infrastructure. Organizations should also consider implementing network monitoring solutions that can detect anomalous behavior patterns consistent with exploitation attempts, and establish incident response procedures to quickly address any successful exploitation attempts. Given the nature of the vulnerability, it is crucial to maintain awareness of other similar buffer overflow vulnerabilities in networking equipment and ensure that all network infrastructure components receive regular security updates and patches to prevent similar exploitation opportunities.