Emissary

Emissary is a Trojan that has been used by Lotus Blossom. It shares code with Elise, with both Trojans being part of a malware group referred to as LStudio. [1]

ID: S0082
Type: MALWARE
Platforms: Windows
Version: 1.0

Techniques Used

Domain ID Name Use
Enterprise T1009 Binary Padding

A variant of Emissary appends junk data to the end of its DLL file to create a large file that may exceed the maximum size that anti-virus programs can scan.[2]

Enterprise T1059 Command-Line Interface

Emissary has the capability to create a remote shell and execute specified commands.[1]

Enterprise T1024 Custom Cryptographic Protocol

The C2 server response to a beacon sent by a variant of Emissary contains a 36-character GUID value that is used as an encryption key for subsequent network communications. Some variants of Emissary use various XOR operations to encrypt C2 data.[1]

Enterprise T1050 New Service

Emissary is capable of configuring itself as a service.[2]

Enterprise T1027 Obfuscated Files or Information

Variants of Emissary encrypt payloads using various XOR ciphers, as well as a custom algorithm that uses the "srand" and "rand" functions.[1][2]

Enterprise T1069 Permission Groups Discovery

Emissary has the capability to execute the command net localgroup administrators.[2]

Enterprise T1055 Process Injection

Emissary injects its DLL file into a newly spawned Internet Explorer process.[1]

Enterprise T1060 Registry Run Keys / Startup Folder

Variants of Emissary have added Run Registry keys to establish persistence.[2]

Enterprise T1105 Remote File Copy

Emissary has the capability to download files from the C2 server.[1]

Enterprise T1085 Rundll32

Variants of Emissary have used rundll32.exe in Registry values added to establish persistence.[2]

Enterprise T1071 Standard Application Layer Protocol

Emissary uses HTTP or HTTPS for C2.[1]

Enterprise T1082 System Information Discovery

Emissary has the capability to execute ver, systeminfo, and gpresult commands.[2]

Enterprise T1016 System Network Configuration Discovery

Emissary has the capability to execute the command ipconfig /all.[2]

Enterprise T1007 System Service Discovery

Emissary has the capability to execute the command net start to interact with services.[2]

Groups That Use This Software

ID Name References
G0030 Lotus Blossom [1] [2]

References