Netwalker

Netwalker is fileless ransomware written in PowerShell and executed directly in memory.[1]

ID: S0457
Type: MALWARE
Platforms: Windows
Version: 1.1
Created: 26 May 2020
Last Modified: 22 March 2023

Techniques Used

Domain ID Name Use
Enterprise T1047 Windows管理规范

Netwalker can use WMI to delete Shadow Volumes.[1]

Enterprise T1112 修改注册表

Netwalker can add the following registry entry: HKEY_CURRENT_USER\SOFTWARE{8 random characters}.[1]

Enterprise T1140 反混淆/解码文件或信息

Netwalker's PowerShell script can decode and decrypt multiple layers of obfuscation, leading to the Netwalker DLL being loaded into memory.[2]

Enterprise T1059 .001 命令与脚本解释器: PowerShell

Netwalker has been written in PowerShell and executed directly in memory, avoiding detection.[1][2]

.003 命令与脚本解释器: Windows Command Shell

Operators deploying Netwalker have used batch scripts to retrieve the Netwalker payload.[2]

Enterprise T1562 .001 妨碍防御: Disable or Modify Tools

Netwalker can detect and terminate active security software-related processes on infected systems.[1][2]

Enterprise T1486 数据加密以实现影响

Netwalker can encrypt files on infected machines to extort victims.[1]

Enterprise T1489 服务停止

Netwalker can terminate system processes and services, some of which relate to backup software.[1]

Enterprise T1106 本机API

Netwalker can use Windows API functions to inject the ransomware DLL.[1]

Enterprise T1570 横向工具传输

Operators deploying Netwalker have used psexec to copy the Netwalker payload across accessible systems.[2]

Enterprise T1027 .009 混淆文件或信息: Embedded Payloads

Netwalker's DLL has been embedded within the PowerShell script in hex format.[1]

.010 混淆文件或信息: Command Obfuscation

Netwalker's PowerShell script has been obfuscated with multiple layers including base64 and hexadecimal encoding and XOR-encryption, as well as obfuscated PowerShell functions and variables.[1][2]

Enterprise T1082 系统信息发现

Netwalker can determine the system architecture it is running on to choose which version of the DLL to use.[1]

Enterprise T1490 系统恢复抑制

Netwalker can delete the infected system's Shadow Volumes to prevent recovery.[1][2]

Enterprise T1569 .002 系统服务: Service Execution

Operators deploying Netwalker have used psexec and certutil to retrieve the Netwalker payload.[2]

Enterprise T1518 .001 软件发现: Security Software Discovery

Netwalker can detect and terminate active security software-related processes on infected systems.[1]

Enterprise T1105 输入工具传输

Operators deploying Netwalker have used psexec and certutil to retrieve the Netwalker payload.[2]

Enterprise T1055 .001 进程注入: Dynamic-link Library Injection

The Netwalker DLL has been injected reflectively into the memory of a legitimate running process.[1]

References