CVE-2021-47835
📋 TL;DR
Freeter 1.2.1 contains a persistent cross-site scripting vulnerability that allows attackers to store malicious scripts in custom widget titles and files. When victims interact with these compromised elements, the scripts execute in their browser context, potentially enabling remote code execution. Users of Freeter 1.2.1 are affected.
💻 Affected Systems
- Freeter
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers achieve remote code execution on victim systems, potentially gaining full control over user workstations and accessing sensitive data.
Likely Case
Attackers execute arbitrary JavaScript in victim browsers, enabling session hijacking, credential theft, and further exploitation.
If Mitigated
Script execution is blocked by browser security controls or content security policies, limiting impact to application functionality disruption.
🎯 Exploit Status
Exploitation requires attackers to create or modify widgets/files that victims will interact with. Public proof-of-concept demonstrates the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch is available. Consider the workarounds below or discontinue use of Freeter 1.2.1.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement server-side validation and sanitization of all user inputs, especially widget titles and file content.
Content Security Policy
allImplement strict Content Security Policy headers to restrict script execution sources.
🧯 If You Can't Patch
- Discontinue use of Freeter 1.2.1 and migrate to alternative software.
- Restrict user permissions to prevent creation/modification of widgets and files.
🔍 How to Verify
Check if Vulnerable:
Check if Freeter version is 1.2.1. Attempt to inject script payloads into widget titles or files and observe if they execute.Check Version:
Check application settings or about dialog for version information.Verify Fix Applied:
Since no official patch exists, verify workarounds by testing script injection attempts after implementing input sanitization and CSP.📡 Detection & Monitoring
Log Indicators:
- Unusual widget or file creation/modification patterns
- Script tags or JavaScript code in widget titles or file metadata
Network Indicators:
- External script loading from unexpected sources in application traffic
SIEM Query:
Search for patterns of script injection in application logs, focusing on widget and file manipulation events.