CVE-2023-45555 in ZZZCMS
Summary
by MITRE • 10/25/2023
File Upload vulnerability in zzzCMS v.2.1.9 allows a remote attacker to execute arbitrary code via a crafted file to the down_url function in zzz.php file.
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Analysis
by VulDB Data Team • 02/10/2026
The CVE-2023-45555 vulnerability represents a critical file upload flaw in zzzCMS version 2.1.9 that exposes systems to remote code execution attacks. This vulnerability specifically targets the down_url function within the zzz.php file, creating a pathway for malicious actors to bypass normal security controls and upload malicious files to the target system. The flaw stems from inadequate input validation and sanitization mechanisms that fail to properly verify the file type and content before processing the upload request. Attackers can exploit this weakness by crafting specially designed files that appear legitimate but contain malicious code, allowing them to execute arbitrary commands on the vulnerable server with the privileges of the web application. This type of vulnerability falls under the CWE-434 category, which specifically addresses "Unrestricted Upload of File with Dangerous Type," representing a well-documented and highly dangerous security flaw in web applications.
The operational impact of this vulnerability extends far beyond simple data theft, as it enables complete system compromise and persistent access for attackers. Once exploited, the remote code execution capability allows threat actors to establish backdoors, deploy additional malware, escalate privileges, and potentially move laterally within network environments. The vulnerability affects the web application layer directly, making it particularly dangerous as it can be exploited through standard web browser interfaces without requiring special tools or extensive reconnaissance. This weakness creates a persistent threat vector that can be leveraged for extended periods, enabling attackers to maintain access while conducting reconnaissance and data exfiltration activities.
Security professionals should consider this vulnerability in the context of the MITRE ATT&CK framework, particularly under the techniques related to "T1190 - Exploit Public-Facing Application" and "T1059.007 - Command and Scripting Interpreter: PowerShell." The vulnerability aligns with ATT&CK's methodology for identifying and categorizing attack patterns that exploit application-level weaknesses to achieve initial access and subsequent system compromise. Organizations should implement comprehensive mitigation strategies including immediate patching of the affected zzzCMS version, implementing strict file type validation, restricting upload permissions to authenticated users only, and deploying web application firewalls to monitor and block suspicious upload attempts. Additionally, regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other web applications within the organization's infrastructure.
The technical implementation of this vulnerability demonstrates poor security practices in input validation and access control mechanisms. The down_url function appears to lack proper file extension checking, MIME type verification, and content analysis capabilities that would normally prevent the upload of executable or malicious files. This flaw indicates a fundamental weakness in the application's security architecture where the system assumes that legitimate users will upload appropriate files without proper verification. The vulnerability represents a classic example of how insufficient security controls at the application layer can lead to complete system compromise. Organizations should also consider implementing multi-factor authentication, regular security updates, and comprehensive logging mechanisms to detect and respond to exploitation attempts. The remediation process should include not only patching the specific vulnerability but also conducting thorough security reviews of similar functions and components throughout the application to prevent similar issues from occurring in other areas of the codebase.