CVE-2014-3430

What it actually does

Incomplete SSL/TLS handshakes for IMAP/POP3 connections are not properly terminated, allowing accumulation of open connections that exhaust server resources and cause denial of service.

Why it matters to the business

Mail services become unavailable due to resource exhaustion, disrupting email operations for users and requiring manual intervention to restore service; the issue affects bundled deployments such as Typo3 via Bitnami.

How an attack unfolds

An attacker repeatedly initiates IMAP or POP3 connections over SSL/TLS but stops the handshake before completion, causing the server to hold each connection open indefinitely until resources are depleted.

How to fix it

Upgrade affected Dovecot installations to 2.2.13 or later (or dovecot-ee 2.1.7.7 / 2.2.12.12 or later); for Typo3 (Bitnami) deployments apply the fixed version 8.7.55.

How to confirm the fix worked

Verify running Dovecot version against the fixed releases; inspect configuration and logs to confirm old connections are now terminated promptly on handshake failure.

Typical attack path

1. Identify exposed IMAP or POP3 endpoints accepting SSL/TLS connections
2. Send numerous connection attempts that begin but do not complete the TLS handshake
3. Monitor server until connection table or memory is exhausted, resulting in denial of service

How to detect it

Examine mail server logs for repeated incomplete TLS handshake attempts from single sources, unusually high counts of connections in early TLS states, and sudden spikes in memory or file descriptor usage.

What your security team should do

• Apply the listed fixed versions immediately on all affected systems
• Review network exposure of IMAP/POP3 services and restrict to trusted networks where possible
• Monitor connection counts and resource usage for anomalies until patches are deployed