Data Encoding: Standard Encoding
Adversaries may encode data with a standard data encoding system to make the content of command and control traffic more difficult to detect. Command and control (C2) information can be encoded using a standard data encoding system that adheres to existing protocol specifications. Common data encoding schemes include ASCII, Unicode, hexadecimal, Base64, and MIME.  Some data encoding systems may also result in data compression, such as gzip.
For C2 over HTTP, Helminth encodes data with base64 and sends it via the "Cookie" field of HTTP requests. For C2 over DNS, Helminth converts ASCII characters into their hexadecimal values and sends the data in cleartext.
|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. 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.
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.
- Wikipedia. (2016, December 26). Binary-to-text encoding. Retrieved March 1, 2017.
- Wikipedia. (2017, February 19). Character Encoding. Retrieved March 1, 2017.
- Kaspersky Lab's Global Research and Analysis Team. (2015, December 4). Sofacy APT hits high profile targets with updated toolset. Retrieved December 10, 2015.
- Grunzweig, J., Lee, B. (2016, January 22). New Attacks Linked to C0d0so0 Group. Retrieved August 2, 2018.
- Ackerman, G., et al. (2018, December 21). OVERRULED: Containing a Potentially Destructive Adversary. Retrieved January 17, 2019.
- Doaty, J., Garrett, P.. (2018, September 10). We’re Seeing a Resurgence of the Demonic Astaroth WMIC Trojan. Retrieved April 17, 2019.
- Settle, A., et al. (2016, August 8). MONSOON - Analysis Of An APT Campaign. Retrieved September 22, 2016.
- Unit 42. (2019, February 22). New BabyShark Malware Targets U.S. National Security Think Tanks. Retrieved October 7, 2019.
- Symantec Security Response. (2014, July 7). Dragonfly: Cyberespionage Attacks Against Energy Suppliers. Retrieved April 8, 2016.
- Levene, B. et al.. (2018, March 7). Patchwork Continues to Deliver BADNEWS to the Indian Subcontinent. Retrieved March 31, 2018.
- Lunghi, D., et al. (2017, December). Untangling the Patchwork Cyberespionage Group. Retrieved July 10, 2018.
- Counter Threat Unit Research Team. (2017, October 12). BRONZE BUTLER Targets Japanese Enterprises. Retrieved January 4, 2018.
- Villeneuve, N., Bennett, J. T., Moran, N., Haq, T., Scott, M., & Geers, K. (2014). OPERATION “KE3CHANG”: Targeted Attacks Against Ministries of Foreign Affairs. Retrieved November 12, 2014.
- Kaspersky Lab's Global Research and Analysis Team. (2015, February). CARBANAK APT THE GREAT BANK ROBBERY. Retrieved August 23, 2018.
- Bennett, J., Vengerik, B. (2017, June 12). Behind the CARBANAK Backdoor. Retrieved June 11, 2018.
- Miller-Osborn, J. and Grunzweig, J.. (2017, February 16). menuPass Returns with New Malware and New Attacks Against Japanese Academics and Organizations. Retrieved March 1, 2017.
- Nakamura, Y.. (2017, February 17). ChChes - Malware that Communicates with C&C Servers Using Cookie Headers. Retrieved March 1, 2017.
- Yadav, A., et al. (2017, August 31). Cobian RAT – A backdoored RAT. Retrieved November 13, 2018.
- FireEye. (2015). APT28: A WINDOW INTO RUSSIA’S CYBER ESPIONAGE OPERATIONS?. Retrieved August 19, 2015.
- Dahan, A. (2017). Operation Cobalt Kitty. Retrieved December 27, 2018.
- Windows Defender Advanced Threat Hunting Team. (2016, April 29). PLATINUM: Targeted attacks in South and Southeast Asia. Retrieved February 15, 2018.
- Chen, J. et al. (2019, November). Operation ENDTRADE: TICK’s Multi-Stage Backdoors for Attacking Industries and Stealing Classified Data. Retrieved June 9, 2020.
- M.Léveillé, M.. (2014, February 21). An In-depth Analysis of Linux/Ebury. Retrieved April 19, 2019.
- Falcone, R., et al.. (2015, June 16). Operation Lotus Blossom. Retrieved February 15, 2016.
- Somerville, L. and Toro, A. (2017, March 30). Playing Cat & Mouse: Introducing the Felismus Malware. Retrieved November 16, 2017.
- Doctor Web. (2014, November 21). Linux.BackDoor.Fysbis.1. Retrieved December 7, 2017.
- Quinn, J. (2019, March 25). The odd case of a Gh0stRAT variant. Retrieved July 15, 2020.
- Falcone, R. and Lee, B.. (2016, May 26). The OilRig Campaign: Attacks on Saudi Arabian Organizations Deliver Helminth Backdoor. Retrieved May 3, 2017.
- US-CERT. (2019, April 10). MAR-10135536-8 – North Korean Trojan: HOPLIGHT. Retrieved April 19, 2019.
- Moran, N., & Villeneuve, N. (2013, August 12). Survival of the Fittest: New York Times Attackers Evolve Quickly [Blog]. Retrieved November 12, 2014.
- Sancho, D., et al. (2012, May 22). IXESHE An APT Campaign. Retrieved June 7, 2019.
- Unit 42. (2017, December 15). Unit 42 Playbook Viewer. Retrieved December 20, 2017.
- Levene, B, et al. (2017, May 03). Kazuar: Multiplatform Espionage Backdoor with API Access. Retrieved July 17, 2018.
- Dumont, R., M.Léveillé, M., Porcher, H. (2018, December 1). THE DARK SIDE OF THE FORSSHE A landscape of OpenSSH backdoors. Retrieved July 16, 2020.
- Karmi, D. (2020, January 4). A Look Into Konni 2019 Campaign. Retrieved April 28, 2020.
- Sherstobitoff, R. (2018, February 12). Lazarus Resurfaces, Targets Global Banks and Bitcoin Users. Retrieved February 19, 2018.
- Falcone, R. (2019, March 4). New Python-Based Payload MechaFlounder Used by Chafer. Retrieved May 27, 2020.
- Gross, J. (2016, February 23). Operation Dust Storm. Retrieved September 19, 2017.
- Villadsen, O.. (2019, August 29). More_eggs, Anyone? Threat Actor ITG08 Strikes Again. Retrieved September 16, 2019.
- ClearSky. (2019, June). Iranian APT group ‘MuddyWater’ Adds Exploits to Their Arsenal. Retrieved May 14, 2020.
- Fidelis Cybersecurity. (2013, June 28). Fidelis Threat Advisory #1009: "njRAT" Uncovered. Retrieved June 4, 2019.
- Kaspersky Lab's Global Research & Analysis Team. (2018, October 15). Octopus-infested seas of Central Asia. Retrieved November 14, 2018.
- Hromcova, Z. (2019, July). OKRUM AND KETRICAN: AN OVERVIEW OF RECENT KE3CHANG GROUP ACTIVITY. Retrieved May 6, 2020.
- Lee, B., Falcone, R. (2018, February 23). OopsIE! OilRig Uses ThreeDollars to Deliver New Trojan. Retrieved July 16, 2018.
- Cymmetria. (2016). Unveiling Patchwork - The Copy-Paste APT. Retrieved August 3, 2016.
- Grunzweig, J., et al. (2016, May 24). New Wekby Attacks Use DNS Requests As Command and Control Mechanism. Retrieved August 17, 2016.
- Lancaster, T. (2018, November 5). Inception Attackers Target Europe with Year-old Office Vulnerability. Retrieved May 8, 2020.
- GReAT. (2019, August 12). Recent Cloud Atlas activity. Retrieved May 8, 2020.
- Lancaster, T.. (2017, November 14). Muddying the Water: Targeted Attacks in the Middle East. Retrieved March 15, 2018.
- Sardiwal, M, et al. (2017, December 7). New Targeted Attack in the Middle East by APT34, a Suspected Iranian Threat Group, Using CVE-2017-11882 Exploit. Retrieved December 20, 2017.
- Cherepanov, A.. (2016, May 17). Operation Groundbait: Analysis of a surveillance toolkit. Retrieved May 18, 2016.
- Lee, B., Falcone, R. (2018, July 25). OilRig Targets Technology Service Provider and Government Agency with QUADAGENT. Retrieved August 9, 2018.
- Falcone, R. (2020, July 22). OilRig Targets Middle Eastern Telecommunications Organization and Adds Novel C2 Channel with Steganography to Its Inventory. Retrieved July 28, 2020.
- Livelli, K, et al. (2018, November 12). Operation Shaheen. Retrieved May 1, 2019.
- Falcone, R., et al. (2018, July 27). New Threat Actor Group DarkHydrus Targets Middle East Government. Retrieved August 2, 2018.
- Cherepanov, A.. (2016, December 13). The rise of TeleBots: Analyzing disruptive KillDisk attacks. Retrieved June 10, 2020.
- Grunzweig, J.. (2015, July 14). Unit 42 Technical Analysis: Seaduke. Retrieved August 3, 2016.
- Check Point Research. (2019, February 4). SpeakUp: A New Undetected Backdoor Linux Trojan. Retrieved April 17, 2019.
- Dahan, A. et al. (2019, December 11). DROPPING ANCHOR: FROM A TRICKBOT INFECTION TO THE DISCOVERY OF THE ANCHOR MALWARE. Retrieved September 10, 2020.
- Chen, J.. (2020, May 12). Tropic Trooper’s Back: USBferry Attack Targets Air gapped Environments. Retrieved May 20, 2020.
- Duncan, B. (2020, July 24). Evolution of Valak, from Its Beginnings to Mass Distribution. Retrieved August 31, 2020.
- CISA. (2020, July 16). MAR-10296782-2.v1 – WELLMESS. Retrieved September 24, 2020.
- Accenture Security. (2018, November 29). SNAKEMACKEREL. Retrieved April 15, 2019.
- Gardiner, J., Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016.