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8649

Port 8649 – Ganglia gmond

TCP/UDP

Port 8649 is the Ganglia monitoring daemon (gmond) port for collecting and sharing host metrics in clusters. Gmond agents exchange metrics via multicast or unicast on port 8649. Ganglia is legacy – most new deployments use Prometheus or Telegraf. Exposed gmond ports leak system metrics but pose minimal direct exploitation risk.

Port Number

8649

Protocol

TCP/UDP

Service

Ganglia Monitoring Daemon

Range

IANA Registered (1024–49151)

Description

Ganglia gmond on port 8649 collects system metrics (CPU, memory, disk, network) and shares them with other gmond instances and gmetad aggregators. In multicast mode, all gmond instances on a subnet share metrics via multicast group 239.2.11.71 on port 8649. Ganglia is largely superseded by Prometheus, Datadog, and Telegraf/InfluxDB stacks. If you encounter port 8649 on a network scan, it typically indicates a legacy HPC (High Performance Computing) or Hadoop cluster. The metrics exposed are informational (system load, memory usage) and do not provide command execution, but they reveal infrastructure details useful for reconnaissance.

Security risks

  • 1Ganglia gmond exposes detailed system metrics (CPU, memory, disk, network) to any host on the multicast group – no authentication mechanism exists in the protocol
  • 2Cluster topology disclosure: gmond broadcasts all node hostnames, IPs, and hardware specs, giving attackers a complete infrastructure map
  • 3CVE-2019-20920: Ganglia gmetad XSS via metric names allows injection of malicious content into the web frontend when gmond forwards crafted metric data
  • 4Default multicast (239.2.11.71) means any host on the same network segment automatically receives all cluster metrics without requesting them
  • 5Legacy protocol with no encryption – all metric data transmitted in plaintext, including custom metrics that may contain sensitive operational data
  • 6gmond's XML TCP port (8649) responds to any TCP connection with full metric dump – no handshake, no auth, instant reconnaissance

Firewall guidance

Block port 8649 TCP/UDP from all external networks. For internal use, restrict to management VLAN only. If multicast is required, use IGMP snooping to limit gmond traffic to monitoring hosts. Modern replacement: deploy Prometheus node_exporter with TLS and bearer token auth instead of Ganglia.

Diagnosis commands

Connect to gmond XML port – dumps full metric tree in XML if exposed (instant recon check)

shell
nc -w 3 host 8649 | head -50

Test gmond TCP listener availability – responds immediately with XML metric dump

shell
telnet host 8649

Query gmond for all cluster metrics in single-shot mode (requires ganglia-monitor-core)

shell
gstat -a -1

Capture gmond multicast traffic and TCP queries to identify active listeners

shell
tcpdump -i eth0 port 8649 or host 239.2.11.71

Scan for gmond on both TCP (interactive query) and UDP (multicast listener)

shell
nmap -sU -sT -p 8649 target

Usage examples

Port 8649 – Ganglia gmond
shell
gmond -c /etc/ganglia/gmond.conf
telnet host 8649 (returns XML metrics dump)
gstat -a shows cluster metrics from gmond

Common services on this port

Ganglia gmond (monitoring daemon)HPC cluster monitoring (Rocks, Bright, xCAT)Legacy Hadoop cluster metrics (pre-Ambari)Scientific computing grid monitoringUniversity research cluster telemetry

Related ports

8651

Ganglia gmetad (collector)

8652

Ganglia gmetad interactive

80

Ganglia Web Frontend (gweb)

9090

Prometheus (modern replacement)

8086

InfluxDB (modern metrics store)

History

Ganglia was created at UC Berkeley in 2000 for monitoring large-scale HPC clusters. Port 8649 was chosen for gmond's XML metric reporting interface, using both multicast UDP for cluster auto-discovery and TCP for on-demand metric queries. Ganglia achieved widespread adoption in scientific computing (TACC, NERSC) and early Hadoop deployments. By 2015, Prometheus and Grafana displaced Ganglia in most production environments due to Ganglia's lack of authentication, push-only model limitations, and abandoned development (last release 2019). Port 8649 remains active primarily in legacy HPC clusters and university research grids that have not migrated.

FAQ

Is Ganglia gmond still maintained?

Ganglia development is effectively abandoned – the last significant release was 3.7.2 in 2019. No security patches are issued. Migrate to Prometheus + node_exporter for authenticated, encrypted, pull-based monitoring with active development and community support.

Can I secure Ganglia gmond without replacing it?

Ganglia has no built-in authentication. Your only option is network-level isolation: bind gmond to a dedicated monitoring VLAN, block port 8649 at the firewall from all non-monitoring hosts, and disable the TCP interactive port if you only need multicast collection. Consider gmond → Prometheus bridge exporters for gradual migration.

What information does gmond leak if port 8649 is exposed?

A single TCP connection to port 8649 returns: all hostnames in the cluster, CPU count/model/speed per host, total/free memory, disk capacity and usage, network interface speeds, OS versions, kernel versions, and any custom metrics. This is a complete infrastructure reconnaissance dump with zero authentication.