CVE-2017-15651 in PRTG Network Monitor
Summary
by MITRE
PRTG Network Monitor 17.3.33.2830 allows remote authenticated administrators to execute arbitrary code by uploading a .exe file and then proceeding in spite of the error message.
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Analysis
by VulDB Data Team • 11/27/2019
PRTG Network Monitor version 17.3.33.2830 contains a critical vulnerability that enables remote authenticated administrators to execute arbitrary code through a file upload flaw. This vulnerability resides in the application's handling of executable file uploads, where the system accepts .exe files despite displaying error messages indicating rejection. The flaw represents a classic bypass mechanism that undermines the intended security controls designed to prevent unauthorized code execution within the monitoring environment. The vulnerability is particularly dangerous because it operates within the context of an authenticated administrative session, eliminating the need for additional privilege escalation.
The technical implementation of this vulnerability stems from inadequate input validation and file type checking mechanisms within the PRTG upload functionality. When administrators attempt to upload malicious executables, the system's validation process fails to properly enforce restrictions, allowing the .exe file to be stored and subsequently executed within the application's environment. This represents a failure in the principle of least privilege and proper access control enforcement, as the system should have rejected the file upload attempt entirely rather than proceeding with execution. The vulnerability demonstrates poor security architecture where error handling and validation logic are not properly synchronized, creating an exploitable gap in the security model.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with persistent code execution capabilities within the network monitoring infrastructure. An authenticated attacker could deploy malware, backdoors, or other malicious payloads that would execute with the privileges of the PRTG service account, potentially leading to complete system compromise. The attack vector is particularly concerning because it requires only administrative credentials, which are often more privileged than typical user accounts and may have broader access to network resources. This vulnerability directly impacts the integrity and confidentiality of network monitoring data, as attackers could manipulate monitoring results, exfiltrate sensitive information, or establish persistent access points within the network infrastructure.
Organizations should immediately implement mitigations including restricting administrative access to the PRTG application, implementing network segmentation to limit potential lateral movement, and deploying additional monitoring controls to detect suspicious file upload activities. The vulnerability aligns with CWE-434 which describes insecure file upload vulnerabilities where applications accept files without proper validation. From an attack perspective, this flaw maps to multiple ATT&CK techniques including execution through file upload and privilege escalation, as the initial access through administrative credentials can lead to broader system compromise. System administrators should also consider implementing file integrity monitoring solutions and restricting the ability to execute files from web application upload directories to prevent exploitation of similar vulnerabilities in the future.