# Memcached

> Memcached is a distributed memory cache. Attackers enumerate keys, dump cached data and session tokens, and test for unauthenticated access and UDP amplification vulnerabilities

- **URL:** https://hackindex.io/services/memcached
- **Type:** Service
- **Default ports:** 11211
- **Tags:** memcached, cache, tcp, udp, linux, web
- **Published:** 2026-01-26
- **Updated:** 2026-07-13

Memcached is a high-performance, distributed in-memory key-value cache used to speed up web applications by caching database queries, API responses, and session data. It listens on **TCP and UDP port 11211**. Nmap identifies it as `memcache`.

Memcached has no built-in authentication or encryption. Any client that can reach port 11211 can read and write cached data. Exposed instances frequently leak session tokens, user credentials, application secrets, and database query results. The UDP protocol support has been exploited in massive DDoS amplification attacks, where a small spoofed request generates a disproportionately large response aimed at the victim.

Enumeration involves connecting via `telnet` or `netcat` and running `stats` to retrieve server information, then `stats items` and `stats cachedump` to list and dump cached keys. Tools like `memcdump` and `memccat` from libmemcached automate extraction. Cached data often contains serialized objects that can be manipulated for deserialization attacks when written back.

## Phases

- [Enumeration](https://hackindex.io/services/memcached/enumeration.md): Nmap, key dumps, UDP checks, SASL, and TLS enum guides (7 guides)
- [Data Exfiltration](https://hackindex.io/services/memcached/data-exfiltration.md): Dump and transfer all Memcached keys and values for offline analysis (1 guides)
- [Vulnerability Discovery](https://hackindex.io/services/memcached/vulnerability-discovery.md): Find exposed cache data and test for UDP amplification risks (2 guides)
- [Exploitation](https://hackindex.io/services/memcached/exploitation.md): Extract cache data and session tokens from unauthenticated Memcached (2 guides)