CVE-2020-7953 in OpMon
Summary
by MITRE
An issue was discovered in OpServices OpMon 9.3.2. Without authentication, it is possible to read server files (e.g., /etc/passwd) due to the use of the nmap -iL (aka input file) option.
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Analysis
by VulDB Data Team • 03/28/2024
The vulnerability identified as CVE-2020-7953 affects OpServices OpMon version 9.3.2 and represents a critical security flaw that undermines the system's authentication mechanisms. This issue allows unauthenticated attackers to access sensitive server files through improper input validation and execution of system commands. The vulnerability specifically exploits the nmap -iL option, which is designed to read targets from an input file, but is being manipulated to access local system resources without proper authorization. This flaw demonstrates a classic path traversal and command injection vulnerability that can be leveraged to extract sensitive information from the target system. The attack vector is particularly dangerous because it requires no prior authentication credentials, making it accessible to any attacker with network access to the affected system.
The technical implementation of this vulnerability stems from the improper handling of user-supplied input within the OpMon application's processing logic. When the nmap -iL option is utilized, the system accepts file paths or input data that should be validated and sanitized before being processed. However, in this case, the application fails to properly validate or restrict the input, allowing attackers to manipulate the command execution flow. The vulnerability is classified under CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal. This weakness enables attackers to access files and directories that are outside the intended scope of the application, potentially leading to information disclosure, system compromise, and further escalation of privileges. The use of nmap's -iL option in this context represents a specific exploitation technique where attackers can feed malicious input files that contain commands or file paths designed to access sensitive system resources.
The operational impact of CVE-2020-7953 is severe and multifaceted, as it provides attackers with unauthorized access to critical system files that could contain sensitive information such as user credentials, system configurations, and network details. Access to files like /etc/passwd can reveal user account information, potentially enabling attackers to identify valid usernames and gain insights into the system's user structure. This vulnerability can serve as a reconnaissance tool for attackers to gather intelligence before launching more sophisticated attacks, and it may also facilitate privilege escalation attempts. The lack of authentication requirements makes this vulnerability particularly dangerous in environments where the affected system is exposed to untrusted networks or lacks proper network segmentation. The impact extends beyond simple information disclosure, as the ability to read arbitrary files can expose system configurations, database connection strings, and other sensitive data that could be leveraged for further compromise. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1005 (Data from Local System), representing a clear path for attackers to gather system information without detection.
Mitigation strategies for CVE-2020-7953 should focus on implementing proper input validation and access controls to prevent unauthorized file access. Organizations should immediately apply the vendor-provided patch or update to OpMon version 9.3.3 or later, which addresses this specific vulnerability. The implementation of proper authentication mechanisms and authorization controls is essential to prevent unauthenticated access to system resources. Network segmentation and firewall rules should be configured to restrict access to the affected system, limiting exposure to only trusted networks and users. Input validation should be strengthened to ensure that any user-supplied data is properly sanitized and validated before being processed by the application. Additionally, implementing principle of least privilege access controls and regular security audits can help prevent similar vulnerabilities from being exploited. System administrators should monitor for unusual file access patterns and implement logging mechanisms to detect potential exploitation attempts. The vulnerability also highlights the importance of secure coding practices and proper input handling, particularly when integrating third-party tools like nmap into application workflows, as demonstrated by the improper use of the -iL option that created this security gap.