CVE-2017-6418

What it actually does

Out-of-bounds read in libclamav/message.c during email parsing leads to process crash (denial of service).

Why it matters to the business

Scanning of email traffic can be disrupted, potentially allowing malware to go undetected or causing operational interruptions in mail gateways and security appliances.

How an attack unfolds

An attacker crafts a specially formatted email message and delivers it to a target system running ClamAV; when the scanner parses the message it reads past allocated buffer bounds and crashes.

How to fix it

Upgrade ClamAV to a build containing commit 586a5180287262070637c8943f2f7efd652e4a2c or later; for tigera-operator-1.33 (Chainguard or Wolfi) upgrade to 1.33.0-r1 or newer.

How to confirm the fix worked

Confirm the installed ClamAV binary or package reports a version after the listed commit; replay a known triggering email sample in a test environment and verify the process no longer crashes.

Typical attack path

1. Craft email with malformed headers or body to trigger the parsing flaw
2. Deliver the message via SMTP or other channel monitored by ClamAV
3. ClamAV initiates scanning of the incoming message
4. Out-of-bounds read occurs resulting in denial of service

How to detect it

Review ClamAV process logs and crash dumps for segmentation faults or out-of-bounds access during email processing; correlate with mail server logs showing sudden scanner restarts around the time of message receipt.

What your security team should do

• Apply the listed fixed versions immediately on all internet-facing or high-volume mail scanners
• Add version checks to continuous compliance scans and package update pipelines
• Monitor upstream ClamAV release notes for any follow-on memory-safety improvements