CVE-2018-0641 in HC100RC
Summary
by MITRE
Buffer overflow in Aterm HC100RC Ver1.0.1 and earlier allows attacker with administrator rights to execute arbitrary code via tools_system.cgi date parameter, time parameter, and offset parameter.
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Analysis
by VulDB Data Team • 04/27/2020
The vulnerability identified as CVE-2018-0641 represents a critical buffer overflow flaw within the Aterm HC100RC Ver1.0.1 and earlier firmware versions. This issue affects network devices that utilize the Aterm HC100RC router model, which is commonly deployed in residential and small office environments. The vulnerability stems from improper input validation within the tools_system.cgi web interface component, which processes date, time, and offset parameters. The flaw exists in the handling of user-supplied data within the web application layer, creating an opportunity for privilege escalation and arbitrary code execution.
The technical implementation of this vulnerability occurs through a classic buffer overflow condition where the system fails to properly validate the length of input parameters passed to the tools_system.cgi script. When an attacker with administrative privileges submits maliciously crafted data through the date, time, or offset parameters, the application does not perform adequate bounds checking before copying the input into fixed-length buffers. This allows the attacker to overwrite adjacent memory locations, potentially corrupting program execution flow and enabling arbitrary code execution. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which is particularly dangerous because it can be exploited to overwrite return addresses and function pointers within the program's execution stack.
The operational impact of this vulnerability is severe and multifaceted for affected organizations and end-users. An attacker with administrative access can leverage this flaw to execute arbitrary code with the privileges of the web server process, typically running as root or SYSTEM. This provides complete control over the affected device, enabling potential network reconnaissance, data exfiltration, or further lateral movement within the network infrastructure. The vulnerability is particularly concerning because it requires only administrative credentials to exploit, which are often default passwords or obtained through social engineering attacks. The attack surface extends beyond the immediate device to potentially compromise other systems within the same network segment.
Mitigation strategies for CVE-2018-0641 should prioritize firmware updates from the vendor, as this represents the most effective solution to address the underlying buffer overflow condition. Organizations should implement network segmentation and access control measures to limit administrative access to these devices, reducing the attack surface for privilege escalation. Network monitoring solutions should be configured to detect anomalous traffic patterns that might indicate exploitation attempts, particularly unusual requests to the tools_system.cgi endpoint. Additionally, implementing web application firewalls and input validation controls can provide additional defense-in-depth layers. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation would likely involve executing system commands through the vulnerable interface. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in network infrastructure devices, particularly those running legacy firmware versions that may be susceptible to similar buffer overflow conditions.