Adversaries may use an existing, legitimate external Web service as a means for relaying data to/from a compromised system. 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.
Use of Web services may also protect back-end C2 infrastructure from discovery through malware binary analysis while also enabling operational resiliency (since this infrastructure may be dynamically changed).
| ID | Name | Description |
|---|---|---|
| G0050 | APT32 |
APT32 has used Dropbox, Amazon S3, and Google Drive to host malicious downloads.[1] |
| S0534 | Bazar | |
| S0635 | BoomBox |
BoomBox can downloaded files from Dropbox using a hardcoded access token.[4] |
| S0335 | Carbon | |
| S0600 | Doki |
Doki has used the dogechain.info API to generate a C2 address.[6] |
| S0547 | DropBook |
DropBook can communicate with its operators by exploiting the Simplenote, DropBox, and the social media platform, Facebook, where it can create fake accounts to control the backdoor and receive instructions.[7][8] |
| G0037 | FIN6 |
FIN6 has used Pastebin and Google Storage to host content for their operations.[9] |
| G0061 | FIN8 |
FIN8 has used |
| G0117 | Fox Kitten |
Fox Kitten has used Amazon Web Services to host C2.[11] |
| G0047 | Gamaredon Group |
Gamaredon Group has used GitHub repositories for downloaders which will be obtained by the group's .NET executable on the compromised system.[12] |
| S0561 | GuLoader |
GuLoader has the ability to download malware from Google Drive.[13] |
| S0601 | Hildegard | |
| G0100 | Inception |
Inception has incorporated at least five different cloud service providers into their C2 infrastructure including CloudMe.[15][16] |
| S0198 | NETWIRE |
NETWIRE has used web services including Paste.ee to host payloads.[17] |
| S0508 | Ngrok |
Ngrok has been used by threat actors to proxy C2 connections to ngrok service subdomains.[18] |
| G0106 | Rocke |
Rocke has used Pastebin, Gitee, and GitLab for Command and Control.[19][20] |
| S0546 | SharpStage |
SharpStage has used a legitimate web service for evading detection.[7] |
| S0589 | Sibot |
Sibot has used a legitimate compromised website to download DLLs to the victim's machine.[21] |
| S0649 | SMOKEDHAM |
SMOKEDHAM has used Google Drive and Dropbox to host files downloaded by victims via malicious links.[22] |
| G0139 | TeamTNT |
TeamTNT has leveraged iplogger.org to send collected data back to C2.[23] |
| G0010 | Turla |
Turla has used legitimate web services including Pastebin, Dropbox, and GitHub for C2 communications.[5][24] |
| 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. |
| ID | Data Source | Data Component |
|---|---|---|
| DS0029 | Network Traffic | Network Connection Creation |
| Network Traffic Content | ||
| Network Traffic Flow |
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.[25]