CVE-2014-3618

What it actually does

Heap-based buffer overflow in formail triggered by crafted email headers with unbalanced quotes, causing memory corruption that leads to denial of service or potential arbitrary code execution.

Why it matters to the business

Legacy email processing servers can be crashed or compromised through incoming messages, disrupting mail flow and exposing outdated systems to remote code execution on unmaintained installations after more than a decade since disclosure.

How an attack unfolds

An attacker sends an email containing a specially crafted header with unbalanced quotes to a target that routes messages through procmail formail for processing; the malformed header triggers the overflow during parsing.

How to fix it

Procmail 3.22 has no official fixed version and is unmaintained; immediately remove or replace it with a modern mail delivery agent such as postfix or maildrop, and audit all dependent Ubuntu systems for removal.

How to confirm the fix worked

Confirm procmail is absent from production paths or replaced; test isolated mail flows with unbalanced-quote headers to verify absence of crashes or overflows.

Typical attack path

1. Craft email header containing unbalanced quotes
2. Send email to recipient processed by vulnerable procmail
3. Trigger formail header parsing
4. Exploit resulting heap corruption for crash or code execution

How to detect it

Review mail and system logs for procmail or formail segmentation faults or crashes during header processing; search historical mail queues for headers containing repeated or unbalanced quote characters.

What your security team should do

• Inventory all systems still running procmail
• Migrate mail processing to supported alternatives within 30 days
• Block or sanitize suspicious headers at the MTA layer if procmail cannot be removed immediately
• Monitor for any remaining instances given the 12-year-old disclosure