Remexi is a Windows-based Trojan that was developed in the C programming language.[1]

ID: S0375
Platforms: Windows
Version: 1.1
Created: 17 April 2019
Last Modified: 30 March 2020

Techniques Used

Domain ID Name Use
Enterprise T1071 .001 Application Layer Protocol: Web Protocols

Remexi uses BITSAdmin to communicate with the C2 server over HTTP.[1]

Enterprise T1010 Application Window Discovery

Remexi has a command to capture active windows on the machine and retrieve window titles.[1]

Enterprise T1560 Archive Collected Data

Remexi encrypts and adds all gathered browser data into files for upload to C2.[1]

Enterprise T1547 .001 Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder

Remexi utilizes Run Registry keys in the HKLM hive as a persistence mechanism.[1]

.004 Boot or Logon Autostart Execution: Winlogon Helper DLL

Remexi achieves persistence using Userinit by adding the Registry key HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit.[1]

Enterprise T1115 Clipboard Data

Remexi collects text from the clipboard.[1]

Enterprise T1059 .003 Command and Scripting Interpreter: Windows Command Shell

Remexi silently executes received commands with cmd.exe.[1]

.005 Command and Scripting Interpreter: Visual Basic

Remexi uses AutoIt and VBS scripts throughout its execution process.[1]

Enterprise T1140 Deobfuscate/Decode Files or Information

Remexi decrypts the configuration data using XOR with 25-character keys.[1]

Enterprise T1041 Exfiltration Over C2 Channel

Remexi performs exfiltration over BITSAdmin, which is also used for the C2 channel.[1]

Enterprise T1083 File and Directory Discovery

Remexi searches for files on the system. [1]

Enterprise T1056 .001 Input Capture: Keylogging

Remexi gathers and exfiltrates keystrokes from the machine.[1]

Enterprise T1027 Obfuscated Files or Information

Remexi obfuscates its configuration data with XOR.[1]

Enterprise T1053 .005 Scheduled Task/Job: Scheduled Task

Remexi utilizes scheduled tasks as a persistence mechanism.[1]

Enterprise T1113 Screen Capture

Remexi takes screenshots of windows of interest.[1]

Enterprise T1047 Windows Management Instrumentation

Remexi executes received commands with wmic.exe (for WMI commands). [1]

Groups That Use This Software

ID Name References
G0087 APT39