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S1099 Samurai

Samurai is a passive backdoor that has been used by ToddyCat since at least 2020. Samurai allows arbitrary C# code execution and is used with multiple modules for remote administration and lateral movement.1

Item Value
ID S1099
Associated Names
Type MALWARE
Version 1.0
Created 04 January 2024
Last Modified 04 January 2024
Navigation Layer View In ATT&CK® Navigator

Techniques Used

Domain ID Name Use
enterprise T1071 Application Layer Protocol -
enterprise T1071.001 Web Protocols Samurai can use a .NET HTTPListener class to receive and handle HTTP POST requests.1
enterprise T1059 Command and Scripting Interpreter -
enterprise T1059.003 Windows Command Shell Samurai can use a remote command module for execution via the Windows command line.1
enterprise T1543 Create or Modify System Process -
enterprise T1543.003 Windows Service Samurai can create a service at HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost to trigger execution and maintain persistence.1
enterprise T1132 Data Encoding -
enterprise T1132.001 Standard Encoding Samurai can base64 encode data sent in C2 communications prior to its encryption.1
enterprise T1005 Data from Local System Samurai can leverage an exfiltration module to download arbitrary files from compromised machines.1
enterprise T1573 Encrypted Channel -
enterprise T1573.001 Symmetric Cryptography Samurai can encrypt C2 communications with AES.1
enterprise T1083 File and Directory Discovery Samurai can use a specific module for file enumeration.1
enterprise T1105 Ingress Tool Transfer Samurai has been used to deploy other malware including Ninja.1
enterprise T1036 Masquerading -
enterprise T1036.005 Match Legitimate Resource Name or Location Samurai has created the directory %COMMONPROGRAMFILES%\Microsoft Shared\wmi\ to contain DLLs for loading successive stages.1
enterprise T1112 Modify Registry The Samurai loader component can create multiple Registry keys to force the svchost.exe process to load the final backdoor.1
enterprise T1106 Native API Samurai has the ability to call Windows APIs.1
enterprise T1095 Non-Application Layer Protocol Samurai can use a proxy module to forward TCP packets to external hosts.1
enterprise T1027 Obfuscated Files or Information Samurai can encrypt the names of requested APIs.1
enterprise T1027.004 Compile After Delivery Samurai can compile and execute downloaded modules at runtime.1
enterprise T1027.007 Dynamic API Resolution Samurai can encrypt API name strings with an XOR-based algorithm.1
enterprise T1027.015 Compression Samurai can deliver its final payload as a compressed, encrypted and base64-encoded blob.1
enterprise T1090 Proxy Samurai has the ability to proxy connections to specified remote IPs and ports through a a proxy module.1
enterprise T1012 Query Registry Samurai can query SOFTWARE\Microsoft\.NETFramework\policy\v2.0 for discovery.1
enterprise T1518 Software Discovery Samurai can check for the presence and version of the .NET framework.1

Groups That Use This Software

ID Name References
G1022 ToddyCat 1

References