Data Encoding: Non-Standard Encoding

Newer variants of BACKSPACE will encode C2 communications with a custom system.^[3]

Bankshot encodes commands from the control server using a range of characters and gzip.^[4]

CHIMNEYSWEEP can use a custom Base64 alphabet for encoding C2.^[5]

Cyclops Blink can use a custom binary scheme to encode messages with specific commands and parameters to be executed.^[6]

InvisiMole can use a modified base32 encoding to encode data within the subdomain of C2 requests.^[7]

NightClub has used a non-standard encoding in DNS tunneling removing any = from the result of base64 encoding, and replacing / characters with -s and + characters with -p.^[8]

Ninja can encode C2 communications with a base64 algorithm using a custom alphabet.^[9]

OceanSalt can encode data with a NOT operation before sending the data to the control server.^[10]

PowGoop can use a modified Base64 encoding mechanism to send data to and from the C2 server.^[11]

RDAT can communicate with the C2 via subdomains that utilize base64 with character substitutions.^[12]

ShadowPad has encoded data as readable Latin characters.^[13]

Small Sieve can use a custom hex byte swapping encoding scheme to obfuscate tasking traffic.^[14][15]

Uroburos can use a custom base62 and a de-facto base32 encoding that uses digits 0-9 and lowercase letters a-z in C2 communications.^[16]

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level. Signatures are often for unique indicators within protocols and may be based on the specific obfuscation technique used by a particular adversary or tool, and will likely be different across various malware families and versions. Adversaries will likely change tool C2 signatures over time or construct protocols in such a way as to avoid detection by common defensive tools.