CVE-2025-54391
📋 TL;DR
This vulnerability in Zimbra Collaboration (ZCS) allows attackers with valid user credentials to bypass Two-Factor Authentication (2FA) protection by adding new 2FA methods without proper verification. This results in unauthorized access to accounts that should be protected by 2FA. All Zimbra Collaboration users with 2FA enabled are affected.
💻 Affected Systems
- Zimbra Collaboration (ZCS)
⚠️ 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
Complete account takeover of any 2FA-protected account by an attacker with valid credentials, leading to data theft, email compromise, and lateral movement within the organization.
Likely Case
Targeted attacks against high-value accounts where attackers obtain credentials through phishing or credential stuffing, then bypass 2FA to gain persistent access.
If Mitigated
Limited impact if strong credential hygiene is maintained, but still represents a significant authentication bypass for compromised accounts.
🎯 Exploit Status
Requires valid user credentials. The vulnerability allows bypassing 2FA verification when adding new authentication methods.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not yet released
Vendor Advisory: https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
Restart Required: Yes
Instructions:
1. Monitor Zimbra Security Advisories for patch release. 2. Apply patch when available. 3. Restart Zimbra services. 4. Verify 2FA functionality post-patch.
🔧 Temporary Workarounds
Disable SOAP endpoint
linuxTemporarily disable the vulnerable EnableTwoFactorAuthRequest SOAP endpoint
# Requires Zimbra admin access and service restart
# Consult Zimbra documentation for SOAP endpoint configuration
Network restriction
linuxRestrict access to Zimbra SOAP endpoints to trusted networks only
iptables -A INPUT -p tcp --dport 7071 -s TRUSTED_NETWORK -j ACCEPT
iptables -A INPUT -p tcp --dport 7071 -j DROP
🧯 If You Can't Patch
- Implement additional authentication layers such as IP whitelisting or client certificate authentication
- Monitor for suspicious 2FA configuration changes and implement alerting for new 2FA method registrations
🔍 How to Verify
Check if Vulnerable:
Test if you can add a new 2FA method without providing current 2FA token via the EnableTwoFactorAuthRequest SOAP endpointCheck Version:
zmcontrol -vVerify Fix Applied:
After patching, verify that adding new 2FA methods requires valid current 2FA token📡 Detection & Monitoring
Log Indicators:
- Multiple 2FA method registration attempts for single user
- 2FA configuration changes without prior successful 2FA verification
- SOAP requests to EnableTwoFactorAuthRequest endpoint
Network Indicators:
- Unusual SOAP traffic patterns to authentication endpoints
- Multiple authentication requests from single source
SIEM Query:
source="zimbra.log" AND "EnableTwoFactorAuthRequest" AND NOT "2FA_verification_successful"