T1048: Exfiltration Over Alternative Protocol
Adversaries may steal data by exfiltrating it over a different protocol 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.
Alternate protocols include FTP, SMTP, HTTP/S, DNS, SMB, or any other network protocol not being used as the main command and control channel. Adversaries may also opt to encrypt and/or obfuscate these alternate channels.
Exfiltration Over Alternative Protocol can be done using various common operating system utilities such as Net/SMB or FTP. On macOS and Linux <code>curl</code> may be used to invoke protocols such as HTTP/S or FTP/S to exfiltrate data from a system.
Many IaaS and SaaS platforms (such as Microsoft Exchange, Microsoft SharePoint, GitHub, and AWS S3) support the direct download of files, emails, source code, and other sensitive information via the web console or Cloud API.
How it's found
Behavioral Detection Strategy for Exfiltration Over Alternative Protocol: Detects unusual outbound file transfer behavior using protocols like FTP, SMB, SMTP, or DNS, involving non-standard processes, off-hour activity, or uncommonly high volume. Detects file exfiltration using tools like curl, scp, or custom binaries over protocols such as FTP, HTTP/S, or DNS tunneling, especially outside baseline user behavior. Detects non-native file transfer via curl, Python scripts, or AppleScript using uncommon protocols like FTP, SMTP, or DNS exfiltration through mDNSResponder abuse. Detects access to cloud APIs or CLI tools to move or sync files from sensitive buckets to external endpoints using protocols like HTTPS or S3 APIs. Detects outbound traffic from hostd/vpxa or guest VM interfaces using unauthorized protocols such as FTP, HTTP POST bursts, or long-lived DNS tunnels.
Sub-techniques
T1048.001: Exfiltration Over Symmetric Encrypted Non-C2 Protocol
Adversaries may steal data by exfiltrating it over a symmetrically 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. Symmetric encryption algorithms are those that use shared or the same keys/secrets on each end of the channel. This requires an exchange or pre-arranged agreement/possession of the value used to encrypt and decrypt data. Network protocols that use asymmetric encryption often utilize symmetric encryption once keys are exchanged, but adversaries may opt to manually share keys and implement symmetric cryptographic algorithms (ex: RC4, AES) vice using mechanisms that are baked into a protocol. This may result in multiple layers of encryption (in protocols that are natively encrypted such as HTTPS) or encryption in protocols that not typically encrypted (such as HTTP or FTP).
T1048.002: Exfiltration Over Asymmetric Encrypted Non-C2 Protocol
Adversaries may steal data by exfiltrating it over an asymmetrically 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. Asymmetric encryption algorithms are those that use different keys on each end of the channel. Also known as public-key cryptography, this requires pairs of cryptographic keys that can encrypt/decrypt data from the corresponding key. Each end of the communication channels requires a private key (only in the procession of that entity) and the public key of the other entity. The public keys of each entity are exchanged before encrypted communications begin. Network protocols that use asymmetric encryption (such as HTTPS/TLS/SSL) often utilize symmetric encryption once keys are exchanged. Adversaries may opt to use these encrypted mechanisms that are baked into a 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. 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.
Standards mapping
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is T1048 Exfiltration Over Alternative Protocol?
Adversaries may steal data by exfiltrating it over a different protocol 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. Alternate protocols include FTP, SMTP, HTTP/S, DNS, SMB, or any other network protocol not being used as the main command and control channel. Adversaries may also opt to encrypt and/or obfuscate these alternate channels. Exfiltration Over Alternative Protocol can be done using various common operating system utilities such as Net/SMB or FTP. On macOS and Linux <code>curl</code> may be used to invoke protocols such as HTTP/S or FTP/S to exfiltrate data from a system. Many IaaS and SaaS platforms (such as Microsoft Exchange, Microsoft SharePoint, GitHub, and AWS S3) support the direct download of files, emails, source code, and other sensitive information via the web console or Cloud API.
Which tactics does T1048 belong to?
T1048 maps to the Exfiltration tactic.
Does TurboPentest test for Exfiltration Over Alternative Protocol?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related MITRE ATT&CK techniques
About this reference
These security references are maintained by IntegSec, an offensive-security firm whose team holds CISSP, OSCP, and OSCE certifications and has run thousands of penetration tests. Content is kept current as tools, standards, and attack techniques evolve.
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