Elastic Security Detection Rules

First Time Seen Memcached Writer

Last updated 3 days ago on 2026-07-30
Created 3 days ago on 2026-07-30

About

Identifies the first successful or no-reply Memcached store command from a client to a server. Memcached commonly has no authentication, so an unauthorized writer can overwrite session tokens, poison cached application content, or alter security-sensitive state. This behavior can enable session hijacking such as the exposure described by CVE-2026-29093.
Tags
Domain: NetworkUse Case: Network Security MonitoringUse Case: Threat DetectionTactic: ImpactData Source: Network Packet CaptureLanguage: kuery
Severity
medium
Risk Score
47
MITRE ATT&CK™

Impact (TA0040)(external, opens in a new tab or window)

↳ Data Manipulation (T1565)(external, opens in a new tab or window)

False Positive Examples
New application servers, autoscaled workloads, cache warmers, deployment jobs, administrative tools, and failover systems may legitimately write to Memcached for the first time. Validate the client and server roles, affected keys, deployment context, and application behavior before escalating.
License
Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type
New Terms Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-network_traffic.memcached-*
Related Integrations

network_traffic(external, opens in a new tab or window)

Query
text code block:
data_stream.dataset:network_traffic.memcached and
client.ip:* and server.ip:* and
network_traffic.memcached.request.command:("set" or "add" or "replace" or "append" or "prepend" or "cas") and
(
  network_traffic.memcached.response.type:("Success" or "success") or
  network_traffic.memcached.response.status_code:0 or
  network_traffic.memcached.request.noreply:true
)

Install detection rules in Elastic Security

Detect First Time Seen Memcached Writer in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).