Standard Non-Application Layer Protocol
|Standard Non-Application Layer Protocol|
|Tactic||Command and Control|
|Platform||Linux, macOS, Windows|
Use of a standard 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), and transport layer protocols, such as the User Datagram Protocol (UDP).
ICMP communication between hosts is one example. Because ICMP is part of the Internet Protocol Suite, it is required to be implemented by all IP-compatible hosts;2 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.
- An APT3 downloader establishes SOCKS5 connections for its initial C2.3
- PLATINUM has used the Intel® Active Management Technology (AMT) Serial-over-LAN (SOL) channel for command and control.4
- BUBBLEWRAP can communicate using SOCKS.5
- Crimson uses a custom TCP protocol for C2.6
- Derusbi binds to a raw socket on a random source port between 31800 and 31900 for C2.7
- Mis-Type network traffic can communicate over a raw socket.8
- Misdat network traffic communicates over a raw socket.8
- MoonWind completes network communication via raw sockets.9
- 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.10
- PHOREAL communicates via ICMP for C2.11
- PlugX can be configured to use raw TCP or UDP for command and control.12
- Some Reaver variants use raw TCP for C2.13
- The Regin malware platform can use ICMP to communicate between infected computers.14
- Remsec is capable of using ICMP, TCP, and UDP for C2.1516
- WINDSHIELD C2 traffic can communicate via TCP raw sockets.11
Properly configure firewalls and proxies to limit outgoing traffic to only necessary ports and through proper network gateway systems.
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.17
Analyze network traffic for ICMP messages or other protocols that contain abnormal data or are not normally seen within or exiting the network.
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.17
- Wikipedia. (n.d.). List of network protocols (OSI model). Retrieved December 4, 2014.
- Microsoft. (n.d.). Internet Control Message Protocol (ICMP) Basics. Retrieved December 1, 2014.
- Moran, N., et al. (2014, November 21). Operation Double Tap. Retrieved January 14, 2016.
- Kaplan, D, et al. (2017, June 7). PLATINUM continues to evolve, find ways to maintain invisibility. Retrieved February 19, 2018.
- FireEye Threat Intelligence. (2015, December 1). China-based Cyber Threat Group Uses Dropbox for Malware Communications and Targets Hong Kong Media Outlets. Retrieved December 4, 2015.
- Huss, D.. (2016, March 1). Operation Transparent Tribe. Retrieved June 8, 2016.
- Fidelis Cybersecurity. (2016, February 29). The Turbo Campaign, Featuring Derusbi for 64-bit Linux. Retrieved March 2, 2016.
- Gross, J. (2016, February 23). Operation Dust Storm. Retrieved September 19, 2017.
- Miller-Osborn, J. and Grunzweig, J.. (2017, March 30). Trochilus and New MoonWind RATs Used In Attack Against Thai Organizations. Retrieved March 30, 2017.
- FireEye Labs. (2015, April). APT30 AND THE MECHANICS OF A LONG-RUNNING CYBER ESPIONAGE OPERATION. Retrieved May 1, 2015.
- Carr, N.. (2017, May 14). Cyber Espionage is Alive and Well: APT32 and the Threat to Global Corporations. Retrieved June 18, 2017.
- Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved January 25, 2016.
- Grunzweig, J. and Miller-Osborn, J. (2017, November 10). New Malware with Ties to SunOrcal Discovered. Retrieved November 16, 2017.
- Kaspersky Lab's Global Research and Analysis Team. (2014, November 24). THE REGIN PLATFORM NATION-STATE OWNAGE OF GSM NETWORKS. Retrieved December 1, 2014.
- Symantec Security Response. (2016, August 8). Backdoor.Remsec indicators of compromise. Retrieved August 17, 2016.
- Kaspersky Lab's Global Research & Analysis Team. (2016, August 9). The ProjectSauron APT. Retrieved August 17, 2016.
- Gardiner, J., Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016.