CVE-2018-18924 in ProjeQtOr
Summary
by MITRE
The image-upload feature in ProjeQtOr 7.2.5 allows remote attackers to execute arbitrary code by uploading a .shtml file with "#exec cmd" because rejected files remain on the server, with predictable filenames, after a "This file is not a valid image" error message.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/03/2025
The vulnerability identified as CVE-2018-18924 resides within the image-upload functionality of ProjeQtOr version 7.2.5, representing a critical security flaw that enables remote code execution through improper file validation and handling mechanisms. This vulnerability stems from the application's inadequate security controls during file processing, specifically when dealing with rejected file uploads that are subsequently stored on the server with predictable naming conventions. The flaw manifests when an attacker uploads a specially crafted .shtml file containing the directive "#exec cmd" which, upon successful upload despite initial rejection, can execute arbitrary commands on the target system.
The technical implementation of this vulnerability aligns with CWE-434, which describes insecure file upload vulnerabilities where applications accept files without proper validation, and CWE-94, which covers improper control of generation of code, particularly when user-provided input is executed as code. The attack vector exploits the predictable filename mechanism where rejected files are stored with consistent naming patterns, allowing attackers to determine the location of their malicious payloads. This vulnerability operates under the principle of file inclusion attacks, where the server processes the .shtml file as executable content rather than treating it as a simple image file, effectively bypassing the intended security boundaries.
The operational impact of this vulnerability extends beyond simple remote code execution, encompassing potential full system compromise and persistent access for threat actors. When attackers successfully upload and execute malicious code through this vulnerability, they gain the ability to perform reconnaissance, escalate privileges, install backdoors, and maintain long-term access to the compromised system. The predictable filename storage mechanism significantly reduces the attack complexity, as attackers do not need to guess file locations or overcome additional obfuscation measures. This vulnerability also represents a significant concern from an attacker's perspective, as it allows for the exploitation of the application's core functionality without requiring authentication or advanced attack techniques, making it particularly dangerous in environments where ProjeQtOr is deployed with default configurations.
Mitigation strategies for CVE-2018-18924 should focus on implementing robust file validation and sanitization measures that prevent the execution of non-image files, regardless of their initial rejection status. Organizations should implement strict file type validation using content-based detection rather than relying solely on file extensions, ensure that rejected files are properly deleted or quarantined without predictable naming, and implement proper input sanitization for all user-supplied content. The solution must address the underlying architectural flaw by ensuring that no uploaded files, even those initially rejected, remain accessible or executable on the server. Additionally, implementing proper access controls, regular security audits, and network segmentation can help reduce the potential impact of successful exploitation attempts, while adherence to security standards such as those defined in the OWASP Top Ten and NIST cybersecurity frameworks should guide the overall remediation approach to prevent similar vulnerabilities from occurring in future deployments.