Non-Application Layer Protocol

Adversaries may use a non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive.[1] Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).

ICMP communication between hosts is one example.[2] Because ICMP is part of the Internet Protocol Suite, it is required to be implemented by all IP-compatible hosts; [3] however, it is not as commonly monitored as other Internet Protocols such as TCP or UDP and may be used by adversaries to hide communications.

ID: T1095
Sub-techniques:  No sub-techniques
Platforms: Linux, Network, Windows, macOS
Data Sources: Network Traffic: Network Traffic Content, Network Traffic: Network Traffic Flow
Requires Network:  Yes
Contributors: Ryan Becwar
Version: 2.1
Created: 31 May 2017
Last Modified: 21 October 2020

Procedure Examples

ID Name Description
S0504 Anchor

Anchor has used ICMP in C2 communications.[4]

G0016 APT29

APT29 has used TCP for C2 communications.[5]

G0022 APT3

An APT3 downloader establishes SOCKS5 connections for its initial C2.[6]

S0456 Aria-body

Aria-body has used TCP in C2 communications.[7]

S0043 BUBBLEWRAP

BUBBLEWRAP can communicate using SOCKS.[8]

S0335 Carbon

Carbon uses TCP and UDP for C2.[9]

S0154 Cobalt Strike

Cobalt Strike can be configured to use TCP for C2 communications.[10]

S0115 Crimson

Crimson uses a custom TCP protocol for C2.[11]

S0498 Cryptoistic

Cryptoistic can use TCP in communications with C2.[12]

S0021 Derusbi

Derusbi binds to a raw socket on a random source port between 31800 and 31900 for C2.[13]

S0502 Drovorub

Drovorub can use TCP to communicate between its agent and client modules.[14]

S0076 FakeM

Some variants of FakeM use SSL to communicate with C2 servers.[15]

G0037 FIN6

FIN6 has used Metasploit Bind and Reverse TCP stagers.[16]

S0032 gh0st RAT

gh0st RAT has used an encrypted protocol within TCP segments to communicate with the C2.[17]

G0125 HAFNIUM

HAFNIUM has used TCP for C2.[18]

S0394 HiddenWasp

HiddenWasp communicates with a simple network protocol over TCP.[19]

S0260 InvisiMole

InvisiMole has used TCP to download additional modules.[20]

S0582 LookBack

LookBack uses a custom binary protocol over sockets for C2 communications.[21]

S0455 Metamorfo

Metamorfo has used raw TCP for C2.[22]

S0084 Mis-Type

Mis-Type network traffic can communicate over a raw socket.[23]

S0083 Misdat

Misdat network traffic communicates over a raw socket.[23]

S0149 MoonWind

MoonWind completes network communication via raw sockets.[24]

S0034 NETEAGLE

If NETEAGLE does not detect a proxy configured on the infected machine, it will send beacons via UDP/6000. Also, after retrieving a C2 IP address and Port Number, NETEAGLE will initiate a TCP connection to this socket. The ensuing connection is a plaintext C2 channel in which commands are specified by DWORDs.[25]

S0198 NETWIRE

NETWIRE can use TCP in C2 communications.[26][27]

G0116 Operation Wocao

Operation Wocao has used a custom protocol for command and control.[28]

S0556 Pay2Key

Pay2Key has sent its public key to the C2 server over TCP.[29]

S0587 Penquin

The Penquin C2 mechanism is based on TCP and UDP packets.[30][31]

S0158 PHOREAL

PHOREAL communicates via ICMP for C2.[32]

S0501 PipeMon

The PipeMon communication module can use a custom protocol based on TLS over TCP.[33]

G0068 PLATINUM

PLATINUM has used the Intel® Active Management Technology (AMT) Serial-over-LAN (SOL) channel for command and control.[34]

S0013 PlugX

PlugX can be configured to use raw TCP or UDP for command and control.[35]

S0055 RARSTONE

RARSTONE uses SSL to encrypt its communication with its C2 server.[36]

S0172 Reaver

Some Reaver variants use raw TCP for C2.[37]

S0019 Regin

The Regin malware platform can use ICMP to communicate between infected computers.[38]

S0125 Remsec

Remsec is capable of using ICMP, TCP, and UDP for C2.[39][40]

S0461 SDBbot

SDBbot has the ability to communicate with C2 with TCP over port 443.[41]

S0596 ShadowPad

ShadowPad has used UDP for C2 communications.[42]

S0436 TSCookie

TSCookie can use ICMP to receive information on the destination server.[43]

S0221 Umbreon

Umbreon provides access to the system via SSH or any other protocol that uses PAM to authenticate.[44]

S0515 WellMail

WellMail can use TCP for C2 communications.[45]

S0155 WINDSHIELD

WINDSHIELD C2 traffic can communicate via TCP raw sockets.[32]

S0430 Winnti for Linux

Winnti for Linux has used ICMP, custom TCP, and UDP in outbound communications.[46]

Mitigations

ID Mitigation Description
M1037 Filter Network Traffic

Filter network traffic to prevent use of protocols across the network boundary that are unnecessary.

M1031 Network Intrusion Prevention

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.

M1030 Network Segmentation

Properly configure firewalls and proxies to limit outgoing traffic to only necessary ports and through proper network gateway systems. Also ensure hosts are only provisioned to communicate over authorized interfaces.

Detection

Analyze network traffic for ICMP messages or other protocols that contain abnormal data or are not normally seen within or exiting the network.[47]

Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.[48]

Monitor and investigate API calls to functions associated with enabling and/or utilizing alternative communication channels.

References

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  3. Microsoft. (n.d.). Internet Control Message Protocol (ICMP) Basics. Retrieved December 1, 2014.
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  18. MSTIC. (2021, March 2). HAFNIUM targeting Exchange Servers with 0-day exploits. Retrieved March 3, 2021.
  19. Sanmillan, I. (2019, May 29). HiddenWasp Malware Stings Targeted Linux Systems. Retrieved June 24, 2019.
  20. Hromcova, Z. and Cherpanov, A. (2020, June). INVISIMOLE: THE HIDDEN PART OF THE STORY. Retrieved July 16, 2020.
  21. Raggi, M. Schwarz, D.. (2019, August 1). LookBack Malware Targets the United States Utilities Sector with Phishing Attacks Impersonating Engineering Licensing Boards. Retrieved February 25, 2021.
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  1. FireEye Labs. (2015, April). APT30 AND THE MECHANICS OF A LONG-RUNNING CYBER ESPIONAGE OPERATION. Retrieved May 1, 2015.
  2. Lambert, T. (2020, January 29). Intro to Netwire. Retrieved January 7, 2021.
  3. Duncan, B. (2020, April 3). GuLoader: Malspam Campaign Installing NetWire RAT. Retrieved January 7, 2021.
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