FortiGuard Labs analyzes a TrickBot variant that abandons HTTP in favor of DNS tunneling for C2 communication. The malware encrypts command data with XOR, hex-encodes it, and embeds it as subdomains in DNS queries sent to 8.8.8.8. Responses hide data inside IPv4 address octets, with IP index bits used to reorder fragmented payloads. Persistence is achieved via Windows Task Scheduler with disguised task names (e.g., 'Wireshark autoupdate'), and configuration is stored in NTFS Alternate Data Streams. Obfuscation includes runtime string decryption and hash-based API resolution. The modular architecture supports 12 C2 response commands covering process hollowing, process doppelgänging, rundll32 execution, PowerShell, and raw shellcode execution. Transfer speed over DNS tunneling measured at ~30.7 KB/s. IOCs, MITRE ATT&CK mappings, and API hash tables are provided.
