Adversaries may use an existing, legitimate external Web service to exfiltrate data rather than their primary command and control channel. Popular Web services acting as an exfiltration mechanism may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to compromise. Firewall rules may also already exist to permit traffic to these services.

Web service providers also commonly use SSL/TLS encryption, giving adversaries an added level of protection.

Zgłoszenia podrzędne

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Tytuł Opis
Exfiltration Over Webhook

Adversaries may exfiltrate data to a webhook endpoint rather than over their primary command and control channel. Webhooks are simple mechanisms for allowing a server to push data over HTTP/S to a client without the need for the client to continuously poll the server.[1] Many public and commercial services, such as Discord, Slack, and webhook.site, support the creation of webhook endpoints that can be used by other services, such as Github, Jira, or Trello.[2] When changes happen in the linked services (such as pushing a repository update or modifying a ticket), these services will automatically post the data to the webhook endpoint for use by the consuming application.

Adversaries may link an adversary-owned environment to a victim-owned SaaS service to achieve repeated Automated Exfiltration of emails, chat messages, and other data.[3] Alternatively, instead of linking the webhook endpoint to a service, an adversary can manually post staged data directly to the URL in order to exfiltrate it.[4]

Access to webhook endpoints is often over HTTPS, which gives the adversary an additional level of protection. Exfiltration leveraging webhooks can also blend in with normal network traffic if the webhook endpoint points to a commonly used SaaS application or collaboration service.[5],[6],[7]

References

  1. RedHat. (2022, June 1). What is a webhook?. Retrieved July 20, 2023.
  2. D. (n.d.). Intro to Webhooks. Retrieved July 20, 2023.
  3. Push Security. (2023, July 31). Webhooks. Retrieved August 4, 2023.
  4. Microsoft Threat Intelligence. (2023, October 3). Defending new vectors: Threat actors attempt SQL Server to cloud lateral movement. Retrieved October 3, 2023.
  5. CyberArk Labs. (2023, April 13). The (Not so) Secret War on Discord. Retrieved July 20, 2023.
  6. Nick Biasini, Edmund Brumaghin, Chris Neal, and Paul Eubanks. (2021, April 7). https://blog.talosintelligence.com/collab-app-abuse/. Retrieved July 20, 2023.
  7. Jossef Harush Kadouri. (2022, March 7). Webhook Party — Malicious packages caught exfiltrating data via legit webhook services. Retrieved July 20, 2023.
Exfiltration to Code Repository

Adversaries may exfiltrate data to a code repository rather than over their primary command and control channel. Code repositories are often accessible via an API (ex: https://api.github.com). Access to these APIs are often over HTTPS, which gives the adversary an additional level of protection.

Exfiltration to a code repository can also provide a significant amount of cover to the adversary if it is a popular service already used by hosts within the network.

Exfiltration to Text Storage Sites

Adversaries may exfiltrate data to text storage sites instead of their primary command and control channel. Text storage sites, such as pastebin[.]com, are commonly used by developers to share code and other information.

Text storage sites are often used to host malicious code for C2 communication (e.g., Stage Capabilities), but adversaries may also use these sites to exfiltrate collected data. Furthermore, paid features and encryption options may allow adversaries to conceal and store data more securely.[1]

Note: This is distinct from Exfiltration to Code Repository, which highlight access to code repositories via APIs.

References

  1. Ciarniello, A. (2019, September 24). What is Pastebin and Why Do Hackers Love It?. Retrieved April 11, 2023.
Exfiltration to Cloud Storage

Adversaries may exfiltrate data to a cloud storage service rather than over their primary command and control channel. Cloud storage services allow for the storage, edit, and retrieval of data from a remote cloud storage server over the Internet.

Examples of cloud storage services include Dropbox and Google Docs. Exfiltration to these cloud storage services can provide a significant amount of cover to the adversary if hosts within the network are already communicating with the service.

Powiązane zgłoszenia

Powiązania
Typ powiązania Zgłoszenie
is related to Techniques
is blocked by Detection Strategy for Exfiltration Over Web Service
is blocked by Restrict Web-Based Content
is blocked by Data Loss Prevention
is blocked by Statutory, Regulatory & Contractual Compliance
is blocked by Continuous Monitoring Policy
is blocked by Inventory of Technology Asset Event Logging
is blocked by Encrypting Data In Transit
is blocked by Sensitive Data Inventories
is blocked by Media Storage
is blocked by Media Transportation
is blocked by Malicious Code Protection (Antimalware)
is blocked by Password-Based Authentication
is blocked by Authenticator Feedback
is blocked by Restrictions on Shared Groups / Accounts
is blocked by Boundary Protection
is blocked by Data Flow Enforcement – Access Control Lists (ACLs)
is blocked by Interconnection Security Agreements (ISAs)
is blocked by Secure Engineering & Architecture Policy
is blocked by Supply Chain Risk Management (SCRM)
is blocked by Provenance
is blocked by Executive Leadership Oversight of Security, Compliance & Resilience Controls
is blocked by Continuous Monitoring
is blocked by Covert Channel Analysis
is blocked by Encrypting Data At Rest
is blocked by Use of External Technology Assets, Applications and/or Services (TAAS)
is blocked by Data Mining Protection
is blocked by Cybersecurity & Data Protection Attributes
is blocked by Account Management
is blocked by Access Enforcement
is blocked by Least Privilege
is blocked by Secure Engineering Principles
is blocked by Third-Party Services