Exfiltration Over Web Service
Exfiltration Over Web Service [T1567]
Last updated
Exfiltration Over Web Service [T1567]
Last updated
Name: Exfiltration Over Web Service
ID: T1567
Tactics:
Sub-Technique: , , ,
Exfiltration Over Web Service (MITRE ATT&CK Technique ID: T1567.002) is a sub-technique of the broader "Exfiltration Over Alternative Protocol" technique within the MITRE ATT&CK framework. Attackers leverage legitimate web services, such as cloud storage platforms, social media, or collaborative tools, to exfiltrate sensitive data from compromised networks. This method often blends in with normal network traffic, making it challenging to detect and mitigate.
Exfiltration Over Web Service involves attackers transferring stolen data from compromised systems or networks to external destinations via legitimate web-based platforms and services. These services typically include cloud storage providers (e.g., Dropbox, Google Drive, OneDrive), collaborative platforms (e.g., Slack, Trello, GitHub), social media sites (e.g., Twitter, Facebook), or APIs provided by legitimate third-party services.
Attackers may use multiple methods to execute this technique, including:
API Calls and Web Requests:
Attackers use legitimate web APIs to upload data directly from compromised hosts.
Authentication tokens or API keys (often stolen or misused) may be employed to access these services.
HTTP/HTTPS POST Requests:
Data is encapsulated within HTTP or HTTPS requests to legitimate domains.
Attackers may encode data (e.g., Base64 encoding) to evade basic detection mechanisms.
Cloud Storage Integration:
Attackers upload data directly to cloud storage services using legitimate client software or command-line interfaces.
Malware or scripts automate data exfiltration, periodically uploading sensitive data to cloud storage.
Social Media and Public Platforms:
Attackers utilize public social media platforms or forums by embedding encoded data within posts, comments, or images.
Data can be obfuscated or steganographically embedded within multimedia files to evade detection.
Real-world execution methods include:
Malware infections that automatically upload stolen credentials or sensitive documents to cloud storage services.
Use of compromised legitimate accounts (e.g., employee credentials) to utilize cloud services for data exfiltration.
Scripts or tools that integrate with popular services' APIs to automate data uploads and exfiltration.
Exfiltration Over Web Service can occur at several stages during an attack lifecycle, including:
Data Exfiltration Stage:
After attackers have successfully accessed and collected sensitive data, they leverage legitimate web services to transfer data externally.
Often used as a final stage of an attack to extract valuable information from the targeted network.
Command and Control (C2) Stage:
Attackers may also use web services to maintain persistent communication channels, sending commands and receiving responses via legitimate platforms.
This method allows attackers to blend in with normal network traffic, making detection challenging.
Common attack scenarios include:
Advanced Persistent Threats (APTs):
Often use legitimate web services to remain undetected over extended periods.
Frequently employed by state-sponsored threat actors to exfiltrate sensitive or classified data.
Insider Threats:
Malicious insiders may leverage cloud storage accounts or collaboration tools to transfer sensitive corporate data externally without raising suspicion.
Ransomware and Data Theft Attacks:
Attackers exfiltrate sensitive data before encrypting systems, using web services to threaten victims with data leaks to extort ransom payments.
Detection of Exfiltration Over Web Service can be challenging due to the legitimate nature of the services involved. However, several detection methods, tools, and Indicators of Compromise (IoCs) can help identify this activity:
Network Traffic Monitoring and Analysis:
Inspecting outbound HTTP/HTTPS traffic for unusual patterns, large data transfers, or frequent connections to cloud storage or social media platforms.
Tools such as Zeek (formerly Bro), Suricata, Snort, or Wireshark can analyze network traffic for suspicious activity.
Behavioral Analytics and Anomaly Detection:
Security Information and Event Management (SIEM) solutions (e.g., Splunk, IBM QRadar, Elastic Security) can identify anomalies, such as abnormal login attempts, unusual data upload volumes, or connections to uncommon web services.
Machine learning-based anomaly detection can highlight deviations from normal user behavior.
Endpoint Detection and Response (EDR) Solutions:
EDR tools (CrowdStrike Falcon, SentinelOne, Microsoft Defender for Endpoint) monitor endpoint behavior and detect unauthorized scripts or malware that interact with web services.
Detection of unusual API calls, scripts, or command-line activities associated with data uploads.
Data Loss Prevention (DLP) Solutions:
DLP solutions can detect and block sensitive data uploads to unauthorized external services or cloud storage platforms.
Monitoring file transfers and data uploads helps identify exfiltration attempts.
Indicators of Compromise (IoCs) specific to Exfiltration Over Web Service include:
Unusual outbound connections or API calls to cloud storage services (e.g., Dropbox, Google Drive, OneDrive).
Sudden increase in data uploads to external web services.
Presence of unfamiliar software or scripts interacting with web APIs.
Logs indicating unauthorized or anomalous access to legitimate web services.
Detecting Exfiltration Over Web Service is critical due to its potential impacts on systems and networks, including:
Data Loss and Intellectual Property Theft:
Attackers may exfiltrate sensitive corporate data, intellectual property, trade secrets, or confidential client information, causing significant financial and reputational damage.
Compliance Violations and Regulatory Penalties:
Data breaches involving sensitive information can result in severe regulatory fines and legal consequences, particularly under frameworks such as GDPR, HIPAA, or PCI DSS.
Operational Disruption and Business Continuity Risks:
Exfiltration incidents can disrupt business operations, leading to downtime, loss of productivity, and increased operational costs.
Increased Risk of Further Attacks:
Successful exfiltration can embolden attackers, leading to further exploitation attempts, ransomware attacks, or persistent threats.
Early detection and rapid response significantly mitigate these impacts by:
Preventing or limiting data loss and unauthorized disclosure.
Reducing the risk of regulatory penalties and compliance violations.
Maintaining business continuity and operational resilience.
Improving organizational security posture and threat response capabilities.
Real-world examples of Exfiltration Over Web Service include:
APT29 (Cozy Bear):
Russian threat actor known for leveraging legitimate web services to exfiltrate data.
Utilized cloud storage services (e.g., Dropbox, Google Drive) to exfiltrate sensitive information from compromised networks, including government and diplomatic entities.
FIN7 Cybercrime Group:
Employed cloud storage platforms, such as Dropbox, to exfiltrate stolen payment card data and financial information from targeted retail and hospitality organizations.
Malware deployed by FIN7 automated data uploads to cloud services, making detection difficult.
DarkHydrus Threat Group:
Utilized Google Drive and other cloud storage services to exfiltrate sensitive data from compromised Middle Eastern government entities.
Attackers used legitimate cloud storage APIs to upload data stealthily.
PowerShell-based Malware (CloudFanta):
Malware leveraging PowerShell scripts to automate data exfiltration via cloud storage services, including Dropbox and Google Drive.
Attackers encoded data before uploading, further complicating detection efforts.
Insider Threat Incidents:
Employees using personal or unauthorized cloud storage accounts (e.g., personal Dropbox or Google Drive accounts) to exfiltrate sensitive corporate data.
Often detected through monitoring data uploads, DLP alerts, or endpoint activity logs.
These examples illustrate the diverse scenarios, tools, and impacts associated with Exfiltration Over Web Service, highlighting the importance of effective detection and mitigation strategies.