Exfiltration Over Alternative Protocol: Exfiltration Over Unencrypted Non-C2 Protocol

Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.

Adversaries may opt to obfuscate this data, without the use of encryption, within network protocols that are natively unencrypted (such as HTTP, FTP, or DNS). This may include custom or publicly available encoding/compression algorithms (such as base64) as well as embedding data within protocol headers and fields.

ID: T1048.003
Sub-technique of:  T1048
Tactic: Exfiltration
Platforms: Linux, Windows, macOS
Contributors: William Cain
Version: 2.0
Created: 15 March 2020
Last Modified: 12 April 2022

Procedure Examples

ID Name Description
S0331 Agent Tesla

Agent Tesla has routines for exfiltration over SMTP, FTP, and HTTP.[1][2][3]

G0050 APT32

APT32's backdoor can exfiltrate data by encoding it in the subdomain field of DNS packets.[4]

G0064 APT33

APT33 has used FTP to exfiltrate files (separately from the C2 channel).[5]

S0190 BITSAdmin

BITSAdmin can be used to create BITS Jobs to upload files from a compromised host.[6]

S0252 Brave Prince

Some Brave Prince variants have used South Korea's Daum email service to exfiltrate information, and later variants have posted the data to a web server via an HTTP post command.[7]

S0335 Carbon

Carbon uses HTTP to send data to the C2 server.[8]

S0674 CharmPower

CharmPower can send victim data via FTP with credentials hardcoded in the script.[9]

S0107 Cherry Picker

Cherry Picker exfiltrates files over FTP.[10]

S0492 CookieMiner

CookieMiner has used the curl --upload-file command to exfiltrate data over HTTP.[11]


CORALDECK has exfiltrated data in HTTP POST headers.[12]

S0050 CosmicDuke

CosmicDuke exfiltrates collected files over FTP or WebDAV. Exfiltration servers can be separately configured from C2 servers.[13]

S0281 Dok

Dok exfiltrates logs of its execution stored in the /tmp folder over FTP using the curl command.[14]

G0037 FIN6

FIN6 has sent stolen payment card data to remote servers via HTTP POSTs.[15]

G0061 FIN8

FIN8 has used FTP to exfiltrate collected data.[16]

S0095 ftp

ftp may be used to exfiltrate data separate from the main command and control protocol.[17][18]

S0487 Kessel

Kessel can exfiltrate credentials and other information via HTTP POST request, TCP, and DNS.[19]


KONNI has used FTP to exfiltrate reconnaissance data out.[20]

G0032 Lazarus Group

Lazarus Group malware SierraBravo-Two generates an email message via SMTP containing information about newly infected victims.[21][22]

G0049 OilRig

OilRig has exfiltrated data over FTP separately from its primary C2 channel over DNS.[23]

S0428 PoetRAT

PoetRAT has used ftp for exfiltration.[24]

S0125 Remsec

Remsec can exfiltrate data via a DNS tunnel or email, separately from its C2 channel.[25]

G0076 Thrip

Thrip has used WinSCP to exfiltrate data from a targeted organization over FTP.[26]

S0466 WindTail

WindTail has the ability to automatically exfiltrate files using the macOS built-in utility /usr/bin/curl.[27]

G0102 Wizard Spider

Wizard Spider has exfiltrated victim information using FTP.[28][29]


ID Mitigation Description
M1057 Data Loss Prevention

Data loss prevention can detect and block sensitive data being sent over unencrypted protocols.

M1037 Filter Network Traffic

Enforce proxies and use dedicated servers for services such as DNS and only allow those systems to communicate over respective ports/protocols, instead of all systems within a network.

M1031 Network Intrusion Prevention

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary command and control infrastructure and malware can be used to mitigate activity at the network level.

M1030 Network Segmentation

Follow best practices for network firewall configurations to allow only necessary ports and traffic to enter and exit the network.[30]


ID Data Source Data Component Detects
DS0017 Command Command Execution

Monitor executed commands and arguments that may steal data by exfiltrating it over a symmetrically encrypted network protocol other than that of the existing command and control channel.

DS0022 File File Access

Monitor files viewed in isolation that may steal data by exfiltrating it over a symmetrically encrypted network protocol other than that of the existing command and control channel.

DS0029 Network Traffic Network Connection Creation

Monitor for newly constructed network connections that are sent or received by untrusted hosts.

Network Traffic Content

Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Network Traffic Flow

Monitor network data for uncommon data flows. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.


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  3. Walter, J. (2020, August 10). Agent Tesla | Old RAT Uses New Tricks to Stay on Top. Retrieved December 11, 2020.
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  1. Elovitz, S. & Ahl, I. (2016, August 18). Know Your Enemy: New Financially-Motivated & Spear-Phishing Group. Retrieved February 26, 2018.
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  8. Grunzweig, J. and Falcone, R.. (2016, October 4). OilRig Malware Campaign Updates Toolset and Expands Targets. Retrieved May 3, 2017.
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  11. Security Response Attack Investigation Team. (2018, June 19). Thrip: Espionage Group Hits Satellite, Telecoms, and Defense Companies. Retrieved July 10, 2018.
  12. Wardle, Patrick. (2019, January 15). Middle East Cyber-Espionage analyzing WindShift's implant: OSX.WindTail (part 2). Retrieved October 3, 2019.
  13. The DFIR Report. (2020, October 8). Ryuk’s Return. Retrieved October 9, 2020.
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