GoldMax

GoldMax is a second-stage C2 backdoor written in Go that was used by APT29 and discovered in early 2021 during the investigation into breaches related to the SolarWinds intrusion. GoldMax uses multiple defense evasion techniques, including avoiding virtualization execution and masking malicious traffic.[1][2]

ID: S0588
Associated Software: SUNSHUTTLE
Type: MALWARE
Platforms: Windows
Version: 1.0
Created: 12 March 2021
Last Modified: 26 April 2021

Associated Software Descriptions

Name Description
SUNSHUTTLE

[2]

Techniques Used

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

GoldMax has used HTTPS and HTTP GET requests with custom HTTP cookies for C2.[1][2]

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

GoldMax can spawn a command shell, and execute native commands.[1][2]

Enterprise T1001 .001 Data Obfuscation: Junk Data

GoldMax has used decoy traffic to surround its malicious network traffic to avoid detection.[1]

Enterprise T1140 Deobfuscate/Decode Files or Information

GoldMax has decoded and decrypted the configuration file when executed.[1][2]

Enterprise T1573 .002 Encrypted Channel: Asymmetric Cryptography

GoldMax has RSA-encrypted its communication with the C2 server.[1]

Enterprise T1041 Exfiltration Over C2 Channel

GoldMax can exfiltrate files over the existing C2 channel.[1][2]

Enterprise T1105 Ingress Tool Transfer

GoldMax can download and execute additional files.[1][2]

Enterprise T1036 .004 Masquerading: Masquerade Task or Service

GoldMax has impersonated systems management software to avoid detection.[1]

.005 Masquerading: Match Legitimate Name or Location

GoldMax appeared as a scheduled task impersonating systems management software within the corresponding ProgramData subfolder.[1]

Enterprise T1027 Obfuscated Files or Information

GoldMax has written AES-encrypted and Base64-encoded configuration files to disk.[1][2]

.002 Software Packing

GoldMax has been packed for obfuscation.[2]

Enterprise T1053 .005 Scheduled Task/Job: Scheduled Task

GoldMax has used scheduled tasks to maintain persistence.[1]

Enterprise T1016 System Network Configuration Discovery

GoldMax retrieved a list of the system's network interface after execution.[1]

Enterprise T1124 System Time Discovery

GoldMax can check the current date-time value of the compromised system, comparing it to the hardcoded execution trigger and can send the current timestamp to the C2 server.[1][2]

Enterprise T1497 .001 Virtualization/Sandbox Evasion: System Checks

GoldMax will check if it is being run in a virtualized environment by comparing the collected MAC address to c8:27:cc:c2:37:5a.[1][2]

.003 Virtualization/Sandbox Evasion: Time Based Evasion

GoldMax has set an execution trigger date and time, stored as an ASCII Unix/Epoch time value.[1]

Groups That Use This Software

ID Name References
G0016 APT29

[1]

References