CVE-2016-6254

What it actually does

Heap-based buffer overflow in parse_packet allows remote attackers to crash the daemon or execute arbitrary code by sending a crafted network packet.

Why it matters to the business

Monitoring infrastructure can be taken offline or fully compromised, disrupting visibility into system health and potentially allowing attackers to pivot into monitored environments.

How an attack unfolds

An attacker sends a maliciously crafted UDP or TCP packet to the collectd network plugin listener; the parse_packet function fails to validate length fields, triggering a heap overflow that can be leveraged for denial of service or code execution.

How to fix it

Upgrade collectd to a build containing commit b589096f907052b3a4da2b9ccc9b0e2e888dfc18 or later release (5.4.3+ or 5.5.2+); disable the network plugin if remote collection is not required.

How to confirm the fix worked

Confirm the running collectd binary or source matches a version after the referenced commit; attempt to reproduce the crash with a minimal test packet in an isolated environment.

Typical attack path

1. Identify exposed collectd instances listening on the network port
2. Craft a packet with oversized or malformed data structures
3. Transmit the packet to trigger the overflow in parse_packet
4. Achieve crash for DoS or leverage the overflow for arbitrary code execution

How to detect it

Review collectd and system logs for abrupt daemon crashes or segmentation faults around the time of suspected exploitation; inspect network traffic for unusual packet sizes directed at collectd ports.

What your security team should do

• Immediately upgrade all collectd deployments to a fixed version
• Restrict network plugin access to trusted collectors only via firewall rules
• Monitor for unexpected daemon restarts or crashes in collectd logs