Exfiltration Over Alternative Protocol: Exfiltration Over Unencrypted Non-C2 Protocol, Sub-technique T1048.003 - Enterprise | MI

Exfiltration Over Alternative Protocol: Exfiltration Over Unencrypted Non-C2 Protocol, Sub-technique T1048.003 - Enterprise | MITRE ATT&CK®
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Techniques
Enterprise
Exfiltration Over Alternative Protocol
Exfiltration Over Unencrypted Non-C2 Protocol
Exfiltration Over Alternative Protocol:
Exfiltration Over Unencrypted Non-C2 Protocol
Other sub-techniques of Exfiltration Over Alternative Protocol (3)
ID
Name
T1048.001
Exfiltration Over Symmetric Encrypted Non-C2 Protocol
T1048.002
Exfiltration Over Asymmetric Encrypted Non-C2 Protocol
T1048.003
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.
[1]
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:
ESXi, Linux, Network Devices, Windows, macOS
Contributors:
Austin Clark, @c2defense; William Cain
Version:
2.2
Created:
15 March 2020
Last Modified:
15 April 2025
Version Permalink
Live Version
Procedure Examples
ID
Name
Description
S0331
Agent Tesla
Agent Tesla
has routines for exfiltration over SMTP, FTP, and HTTP.
[2]
[3]
[4]
G0050
APT32
APT32
's backdoor can exfiltrate data by encoding it in the subdomain field of DNS packets.
[5]
G0064
APT33
APT33
has used FTP to exfiltrate files (separately from the C2 channel).
[6]
S0190
BITSAdmin
BITSAdmin
can be used to create
BITS Jobs
to upload files from a compromised host.
[7]
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.
[8]
C0017
C0017
During
C0017
APT41
exfiltrated victim data via DNS lookups by encoding and prepending it as subdomains to the attacker-controlled domain.
[9]
S0335
Carbon
Carbon
uses HTTP to send data to the C2 server.
[10]
S1043
ccf32
ccf32
can upload collected data and files to an FTP server.
[11]
S0674
CharmPower
CharmPower
can send victim data via FTP with credentials hardcoded in the script.
[12]
S0107
Cherry Picker
Cherry Picker
exfiltrates files over FTP.
[13]
S0492
CookieMiner
CookieMiner
has used the
curl --upload-file
command to exfiltrate data over HTTP.
[14]
S0212
CORALDECK
CORALDECK
has exfiltrated data in HTTP POST headers.
[15]
S0050
CosmicDuke
CosmicDuke
exfiltrates collected files over FTP or WebDAV. Exfiltration servers can be separately configured from C2 servers.
[16]
S0281
Dok
Dok
exfiltrates logs of its execution stored in the
/tmp
folder over FTP using the
curl
command.
[17]
G0037
FIN6
FIN6
has sent stolen payment card data to remote servers via HTTP POSTs.
[18]
G0061
FIN8
FIN8
has used FTP to exfiltrate collected data.
[19]
S0095
ftp
ftp
may be used to exfiltrate data separate from the main command and control protocol.
[20]
[21]
S0487
Kessel
Kessel
can exfiltrate credentials and other information via HTTP POST request, TCP, and DNS.
[22]
S0356
KONNI
KONNI
has used FTP to exfiltrate reconnaissance data out.
[23]
G0032
Lazarus Group
Lazarus Group
malware SierraBravo-Two generates an email message via SMTP containing information about newly infected victims.
[24]
[25]
G0049
OilRig
OilRig
has exfiltrated data via Microsoft Exchange and over FTP separately from its primary C2 channel over DNS.
[26]
[27]
S0428
PoetRAT
PoetRAT
has used
ftp
for exfiltration.
[28]
S1040
Rclone
Rclone
can exfiltrate data over FTP or HTTP, including HTTP via WebDAV.
[29]
S0125
Remsec
Remsec
can exfiltrate data via a DNS tunnel or email, separately from its C2 channel.
[30]
G1045
Salt Typhoon
Salt Typhoon
has exfiltrated configuration files from exploited network devices over FTP and TFTP.
[31]
S1124
SocGholish
SocGholish
can exfiltrate data directly to its C2 domain via HTTP.
[32]
G0076
Thrip
Thrip
has used WinSCP to exfiltrate data from a targeted organization over FTP.
[33]
S1116
WARPWIRE
WARPWIRE
can send captured credentials to C2 via HTTP
GET
or
POST
requests.
[34]
[35]
S0466
WindTail
WindTail
has the ability to automatically exfiltrate files using the macOS built-in utility /usr/bin/curl.
[36]
G0102
Wizard Spider
Wizard Spider
has exfiltrated victim information using FTP.
[37]
[38]
Mitigations
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.
[39]
Detection
ID
Data Source
Data Component
Detects
DS0017
Command
Command Execution
Monitor for execution of exfiltration-related commands such as ftp, curl, scp, tftp, use of Base64 encoding, gzip, or other obfuscation before transmission, or use of CLI-based copy commands to move files to external destinations.
Analytic 1 - Detecting Unencrypted Exfiltration via Command Execution
(EventCode=1 OR source="/var/log/audit/audit.log" type="execve")| where (command IN ("ftp", "curl -T", "wget --post-file", "scp", "rsync", "tftp", "base64"))| eval risk_score=case( command IN ("ftp", "scp", "tftp"), 9, command IN ("base64", "gzip", "tar"), 8)| where risk_score >= 8| stats count by _time, host, user, command, risk_score
DS0022
File
File Access
Monitor files being accessed and staged before unencrypted exfiltration, creation of compressed archives before network transmission, or presence of encoded file formats that indicate obfuscation (.b64, .zip, .tar).
Analytic 1 - Detecting File Access Before Unencrypted Exfiltration
(EventCode=11 OR EventCode=4663 OR source="/var/log/audit/audit.log" type="open")| where (file_path IN ("/tmp/
", "/var/tmp/
", "/home/
/Downloads/
", "C:\Users\*\Documents\exfil") AND file_extension IN ("b64", "tar", "zip"))| eval risk_score=case( file_extension="b64" OR file_extension="tar", 9, file_extension="zip", 8)| where risk_score >= 8| stats count by _time, host, user, file_path, file_extension, risk_score
DS0029
Network Traffic
Network Connection Creation
Monitor for unencrypted outbound network connections involving file transfer protocols, processes sending significantly more data than they receive, or outbound data transfers occurring at unusual times.
Analytic 1 - Detecting Exfiltration Over Unencrypted Alternative Protocols
(EventCode=3 OR source="zeek_conn.log" OR source="firewall_logs")| where (dest_port IN (21, 53, 69, 139, 445, 8080) AND bytes_out > 10000000)| stats count, sum(bytes_out) as total_bytes by _time, host, process, dest_ip, dest_port| where count >= 3 AND total_bytes > 50000000| eval risk_score=case( total_bytes > 100000000, 9, total_bytes > 50000000, 8)| where risk_score >= 8| table host, dest_ip, total_bytes, dest_port, risk_score
Network Traffic Content
Monitor for data obfuscation methods such as Base64, XOR, or URL encoding in HTTP requests, use of TFTP, FTP, or DNS for data exfiltration, or outbound requests containing encoded strings in GET or POST parameters.
Analytic 1 - Detecting Encoded Data in Unencrypted Alternative Protocols
(EventCode=3 OR source="zeek_http.log" OR source="dns.log")| where (uri_length > 200 OR request_body_length > 5000)| eval encoded_data=if(match(uri, "([A-Za-z0-9+/=]{100,})") OR match(request_body, "([A-Za-z0-9+/=]{100,})"), 1, 0)| where encoded_data=1| stats count by _time, host, user, uri, request_body_length, risk_score| eval risk_score=case( request_body_length > 10000, 9, request_body_length > 5000, 8)| where risk_score >= 8| table host, uri, request_body_length, risk_score
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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