CyberStack

MITRE ATT&CK / Techniques / T1505.003

Server Software Component: Web Shell

ID
T1505.003
Tactics
TA0003 Persistence
Sub-technique of
T1505 Server Software Component
Platforms
Linux, macOS, Network Devices, Windows
Data sources
File Creation, Process Creation, Logon Session Creation, Network Traffic Content, File Modification
Source
attack.mitre.org
MITRE last modified
12 May 2026

Adversaries may backdoor web servers with web shells to establish persistent access to systems. A Web shell is a Web script that is placed on an openly accessible Web server to allow an adversary to access the Web server as a gateway into a network. A Web shell may provide a set of functions to execute or a command-line interface on the system that hosts the Web server.[3]

In addition to a server-side script, a Web shell may have a client interface program that is used to talk to the Web server (e.g. China Chopper Web shell client).[4]

Detection

Mitigations (2)

M1018 User Account Management

Enforce the principle of least privilege by limiting privileges of user accounts so only authorized accounts can modify the web directory.[1]

M1042 Disable or Remove Feature or Program

Consider disabling functions from web technologies such as PHP’s evaI() that may be abused for web shells.[2]

Groups (31)

Software (22)

References

  1. NSA and ASD Detect and Prevent Web Shells 2020
  2. ITSyndicate Disabling PHP functions
  3. volexity_0day_sophos_FW
  4. Lee 2013