Web Service: Bidirectional Communication

Adversaries may use an existing, legitimate external Web service as a means for sending commands to and receiving output from a compromised system over the Web service channel. Compromised systems may leverage popular websites and social media to host command and control (C2) instructions. Those infected systems can then send the output from those commands back over that Web service channel. The return traffic may occur in a variety of ways, depending on the Web service being utilized. For example, the return traffic may take the form of the compromised system posting a comment on a forum, issuing a pull request to development project, updating a document hosted on a Web service, or by sending a Tweet.

Popular websites and social media acting as a mechanism for C2 may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.

ID: T1102.002
Sub-technique of:  T1102
Platforms: Linux, Windows, macOS
Permissions Required: User
Data Sources: Network Traffic: Network Connection Creation, Network Traffic: Network Traffic Content, Network Traffic: Network Traffic Flow
Version: 1.0
Created: 14 March 2020
Last Modified: 26 March 2020

Procedure Examples

ID Name Description
G0005 APT12

APT12 has used blogs and WordPress for C2 infrastructure.[1]

G0007 APT28

APT28 has used Google Drive for C2.[2]

G0016 APT29

APT29 has used social media platforms to hide communications to C2 servers.[3]

G0067 APT37

APT37 leverages social networking sites and cloud platforms (AOL, Twitter, Yandex, Mediafire, pCloud, Dropbox, and Box) for C2.[4][5]

G0087 APT39

APT39 has communicated with C2 through files uploaded to and downloaded from DropBox.[6]

S0128 BADNEWS

BADNEWS can use multiple C2 channels, including RSS feeds, Github, forums, and blogs.[7][8][9]

S0069 BLACKCOFFEE

BLACKCOFFEE has also obfuscated its C2 traffic as normal traffic to sites such as Github.[10][11]

S0025 CALENDAR

The CALENDAR malware communicates through the use of events in Google Calendar.[12][13]

G0008 Carbanak

Carbanak has used a VBScript named "ggldr" that uses Google Apps Script, Sheets, and Forms services for C2.[14]

S0054 CloudDuke

One variant of CloudDuke uses a Microsoft OneDrive account to exchange commands and stolen data with its operators.[15]

S0244 Comnie

Comnie uses blogs and third-party sites (GitHub, tumbler, and BlogSpot) to avoid DNS-based blocking of their communication to the command and control server.[16]

S0126 ComRAT

ComRAT has the ability to use the Gmail web UI to receive commands and exfiltrate information.[17][18]

S0046 CozyCar

CozyCar uses Twitter as a backup C2 channel to Twitter accounts specified in its configuration file.[19]

S0538 Crutch

Crutch can use Dropbox to receive commands and upload stolen data.[20]

S0213 DOGCALL

DOGCALL is capable of leveraging cloud storage APIs such as Cloud, Box, Dropbox, and Yandex for C2.[4][21]

S0363 Empire

Empire can use Dropbox and GitHub for C2.[22]

G0046 FIN7

FIN7 used legitimate services like Google Docs, Google Scripts, and Pastebin for C2.[23]

S0026 GLOOXMAIL

GLOOXMAIL communicates to servers operated by Google using the Jabber/XMPP protocol.[12][24]

S0531 Grandoreiro

Grandoreiro can utilize web services including Google sites to send and receive C2 data.[25][26]

S0215 KARAE

KARAE can use public cloud-based storage providers for command and control.[4]

S0265 Kazuar

Kazuar has used compromised WordPress blogs as C2 servers.[27]

S0042 LOWBALL

LOWBALL uses the Dropbox cloud storage service for command and control.[28]

G0059 Magic Hound

Magic Hound malware can use a SOAP Web service to communicate with its C2 server.[29]

G0069 MuddyWater

MuddyWater has used web services including OneHub to distribute remote access tools.[30]

S0229 Orz

Orz has used Technet and Pastebin web pages for command and control.[31]

S0216 POORAIM

POORAIM has used AOL Instant Messenger for C2.[4]

S0393 PowerStallion

PowerStallion uses Microsoft OneDrive as a C2 server via a network drive mapped with net use.[32]

S0511 RegDuke

RegDuke can use Dropbox as its C2 server.[3]

S0379 Revenge RAT

Revenge RAT used blogpost.com as its primary command and control server during a campaign.[33]

S0270 RogueRobin

RogueRobin has used Google Drive as a Command and Control channel. [34]

S0240 ROKRAT

ROKRAT leverages legitimate social networking sites and cloud platforms (Twitter, Yandex, and Mediafire) for C2 communications.[35][36]

G0034 Sandworm Team

Sandworm Team has used the Telegram Bot API from Telegram Messenger to send and receive commands to its Python backdoor. Sandworm Team also used legitimate M.E.Doc software update check requests for sending and receiving commands and hosted malicious payloads on putdrive.com.[37][38]

S0218 SLOWDRIFT

SLOWDRIFT uses cloud based services for C2.[4]

G0010 Turla

A Turla JavaScript backdoor has used Google Apps Script as its C2 server.[39][40]

S0333 UBoatRAT

UBoatRAT has used GitHub and a public blog service in Hong Kong for C2 communications.[41]

S0248 yty

yty communicates to the C2 server by retrieving a Google Doc.[42]

G0128 ZIRCONIUM

ZIRCONIUM has used Dropbox for C2 allowing upload and download of files as well as execution of arbitrary commands.[43][44]

Mitigations

ID Mitigation Description
M1031 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.

M1021 Restrict Web-Based Content

Web proxies can be used to enforce external network communication policy that prevents use of unauthorized external services.

Detection

Host data that can relate unknown or suspicious process activity using a network connection is important to supplement any existing indicators of compromise based on malware command and control signatures and infrastructure or the presence of strong encryption. Packet capture analysis will require SSL/TLS inspection if data is encrypted. Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). User behavior monitoring may help to detect abnormal patterns of activity.[45]

References

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