CVE-2019-25337
📋 TL;DR
CVE-2019-25337 is a username enumeration vulnerability in ownCloud that allows remote attackers to discover valid user accounts by sending crafted requests to the share.php endpoint. This affects ownCloud 8.1.8 installations, potentially exposing user information to unauthorized parties.
💻 Affected Systems
- ownCloud
⚠️ 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 can enumerate all valid usernames, enabling targeted credential attacks, social engineering, or further exploitation of known user accounts.
Likely Case
Attackers discover valid usernames to conduct password spraying or brute force attacks against the ownCloud instance.
If Mitigated
With proper network controls and monitoring, enumeration attempts are detected and blocked before significant information disclosure occurs.
🎯 Exploit Status
Exploit code is publicly available on Exploit-DB (ID 47745). The attack requires only HTTP GET requests with specific parameters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ownCloud 8.1.9 and later
Vendor Advisory: https://owncloud.org/security/advisory/?id=oc-sa-2019-001
Restart Required: No
Instructions:
1. Backup your ownCloud installation and database. 2. Download ownCloud 8.1.9 or later from the official repository. 3. Replace the affected files with the patched version. 4. Verify the installation is functioning correctly.
🔧 Temporary Workarounds
Web Application Firewall Rule
linuxBlock requests to /index.php/core/ajax/share.php with wildcard search parameters
# Example ModSecurity rule: SecRule REQUEST_URI "@contains /index.php/core/ajax/share.php" "id:1001,phase:2,deny,status:403,msg:'Block ownCloud username enumeration'"
Access Restriction
allRestrict access to the share.php endpoint to authenticated users only
# In .htaccess or web server config: <Location "/index.php/core/ajax/share.php">
Require valid-user
</Location>
🧯 If You Can't Patch
- Implement network-level restrictions to limit access to the ownCloud instance to trusted IP addresses only
- Enable detailed logging and monitoring for suspicious requests to the share.php endpoint
🔍 How to Verify
Check if Vulnerable:
Send a GET request to /index.php/core/ajax/share.php?search=* and check if user information is returned in the responseCheck Version:
Check the ownCloud admin panel or run: grep -i version /path/to/owncloud/version.phpVerify Fix Applied:
After patching, attempt the same request and verify no user information is disclosed📡 Detection & Monitoring
Log Indicators:
- Multiple GET requests to /index.php/core/ajax/share.php with wildcard parameters
- Unusual patterns of requests to the share endpoint from single IPs
Network Indicators:
- HTTP requests containing 'search=*' parameter to the share.php endpoint
- Unusual traffic patterns to the ownCloud web interface
SIEM Query:
source="owncloud_access.log" AND uri="/index.php/core/ajax/share.php" AND query="*search=*"