CVE-2021-39383
📋 TL;DR
DWSurvey v3.2.0 contains a remote command execution vulnerability in the SysPropertyAction.java component that allows attackers to execute arbitrary commands on the server. This affects all systems running the vulnerable version of DWSurvey survey software. Attackers can potentially take full control of affected servers.
💻 Affected Systems
- DWSurvey
📦 What is this software?
Dwsurvey by Diaowen
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise allowing data theft, ransomware deployment, lateral movement to other systems, and persistent backdoor installation.
Likely Case
Server takeover leading to data exfiltration, website defacement, cryptocurrency mining, or use as part of a botnet.
If Mitigated
Limited impact if proper network segmentation, least privilege, and monitoring are in place, though server compromise is still possible.
🎯 Exploit Status
Exploitation requires authentication to the DWSurvey system. The vulnerability is well-documented in public GitHub issues with technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v3.2.1 or later
Vendor Advisory: https://github.com/wkeyuan/DWSurvey/issues/81
Restart Required: Yes
Instructions:
1. Backup your DWSurvey data and configuration. 2. Download the latest version from the official repository. 3. Replace the vulnerable files with patched versions. 4. Restart the DWSurvey application server. 5. Verify the fix by checking the version.
🔧 Temporary Workarounds
Access Control Restriction
allRestrict access to the /sysuser/SysPropertyAction endpoint using web application firewall or network controls.
# Example nginx location block to restrict access
location ~ ^/sysuser/SysPropertyAction {
deny all;
return 403;
}
Authentication Hardening
allImplement strong authentication requirements and monitor for suspicious login attempts to the DWSurvey admin interface.
# Enable detailed authentication logging in application configuration
# Set strong password policies
# Implement multi-factor authentication if available
🧯 If You Can't Patch
- Isolate the DWSurvey server in a restricted network segment with no internet access
- Implement strict network monitoring and alerting for suspicious command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check if your DWSurvey installation is version 3.2.0 by examining the version file or application properties.Check Version:
grep -r 'version' /path/to/dwsurvey/ | grep -i '3.2.0'Verify Fix Applied:
Verify the version is updated to 3.2.1 or later and test that the SysPropertyAction endpoint no longer accepts malicious input.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in system logs
- Multiple failed authentication attempts followed by successful login
- Access to SysPropertyAction endpoint with suspicious parameters
Network Indicators:
- Outbound connections from DWSurvey server to unusual destinations
- Unexpected process execution on the server
SIEM Query:
source="dwsurvey" AND (url="/sysuser/SysPropertyAction" OR cmd="*" OR process="bash")