Search Closed Sources

Search Closed Sources [T1597]

Information

• Name: Search Closed Sources

• ID: T1597

• Tactics: TA0043

• Sub-Technique: T1597.002, T1597.001

Introduction

"Search Closed Sources" (T1597.001) is a sub-technique under the broader "Reconnaissance" tactic within the MITRE ATT&CK framework. Attackers leverage this technique to gather information from closed or restricted sources that are not publicly accessible, such as subscription-based databases, private forums, or proprietary information repositories. This information gathering often precedes active exploitation and helps attackers refine their strategies, identify sensitive targets, and better understand the internal structure and vulnerabilities of an organization.

Deep Dive Into Technique

The "Search Closed Sources" technique involves attackers accessing and analyzing information stored in closed, restricted, or subscription-based platforms to gather intelligence on potential targets. These sources typically require authentication, membership, or subscription fees, and the information they contain is not indexed publicly by search engines.

Technical details and execution methods include:

• Credential Acquisition and Abuse:

  • Attackers may obtain credentials through phishing, credential stuffing, or purchasing stolen credentials on dark web marketplaces.

  • Legitimate but compromised user accounts are used to access closed sources without raising immediate suspicion.

• Subscription-Based Platforms and Databases:

  • Attackers subscribe or gain unauthorized access to paid databases or industry-specific repositories containing sensitive corporate or personal data.

  • Common examples include financial databases, academic journals, industry-specific reports, and intelligence platforms.

• Private Forums and Communities:

  • Attackers infiltrate private or invite-only forums, chat rooms, or social media groups to gather sensitive information shared between trusted members.

  • These forums may provide insider information, leaked credentials, or sensitive documents not publicly available.

• Internal Documentation and Intranets:

  • Attackers may exploit compromised credentials or vulnerabilities to access internal documentation repositories (e.g., SharePoint, Confluence, internal wikis).

  • Such internal resources often contain sensitive organizational information, security procedures, network diagrams, and employee details.

Real-world procedures attackers employ include:

• Using compromised credentials to access subscription-based threat intelligence platforms.

• Leveraging leaked credentials to access private GitHub repositories containing proprietary source code or configuration files.

• Exploiting weak authentication mechanisms to infiltrate private Slack or Discord channels.

When this Technique is Usually Used

Attack scenarios and stages where "Search Closed Sources" typically appear include:

• Reconnaissance Stage:

  • Early in the attack lifecycle, attackers gather intelligence to identify potential targets, vulnerabilities, and sensitive information.

  • Closed sources provide high-quality, reliable information not available publicly.

• Initial Access Preparation:

  • Attackers gather credentials, internal documentation, and network diagrams to plan initial access vectors and targeted phishing campaigns.

• Privilege Escalation and Lateral Movement Preparation:

  • Information from closed sources helps attackers understand internal structures, employee roles, and potential privilege escalation paths.

• Targeted Spear Phishing Campaigns:

  • Attackers use insider information from private forums or closed databases to craft convincing spear phishing emails tailored specifically to targeted individuals or groups.

• Competitive Espionage:

  • Advanced persistent threats (APTs) or corporate espionage actors use closed sources to gain strategic insights into competitors' proprietary research, financial data, or intellectual property.

How this Technique is Usually Detected

Detection methods, tools, and specific indicators of compromise (IoCs) include:

• Monitoring Authentication Logs:

  • Track and analyze login attempts and access patterns to subscription-based databases and internal repositories.

  • Identify abnormal logins from unusual IP addresses, geolocations, or at unexpected times.

• Behavioral Analytics and Anomaly Detection:

  • Utilize User and Entity Behavior Analytics (UEBA) tools to detect deviations from normal user behavior patterns when accessing sensitive or closed resources.

  • Identify unusual spikes in data access or downloads.

• Endpoint Detection and Response (EDR) Tools:

  • Deploy endpoint security solutions to detect unauthorized access attempts, credential misuse, and suspicious file downloads.

• Network Traffic Analysis:

  • Analyze network logs and traffic patterns for unusual access to subscription-based services or internal documentation platforms.

  • Detect connections to known closed-source platforms from abnormal endpoints or external IP addresses.

• Threat Intelligence and Dark Web Monitoring:

  • Monitor dark web marketplaces and private forums for leaked credentials or sensitive organizational data.

  • Subscribe to threat intelligence feeds that report compromised credentials and data breaches.

Specific Indicators of Compromise (IoCs):

• Repeated failed login attempts to subscription-based databases or internal documentation platforms.

• Access from unusual or foreign IP addresses or VPN/proxy services.

• Sudden increase in downloads or data access from closed sources.

• Presence of stolen organizational credentials or sensitive documents on dark web or private forums.

Why it is Important to Detect This Technique

Detecting the "Search Closed Sources" technique early is critical due to its potential impacts on systems and networks, including:

• Preparation for Targeted Attacks:

  • Attackers often use intelligence gathered from closed sources to tailor highly effective spear phishing or social engineering campaigns, increasing their likelihood of success.

• Data Breach and Intellectual Property Theft:

  • Attackers may use compromised credentials to access sensitive intellectual property, proprietary research, or financial data, leading to significant financial and reputational damage.

• Compromise of Sensitive Credentials:

  • Early detection helps prevent attackers from leveraging stolen credentials for lateral movement, privilege escalation, or persistent access.

• Operational Disruption:

  • Attackers who successfully infiltrate closed internal sources can disrupt business operations, leak sensitive internal communications, or sabotage critical internal processes.

• Regulatory and Compliance Risks:

  • Unauthorized access to sensitive data stored in closed sources can expose organizations to regulatory fines, lawsuits, and compliance violations (e.g., GDPR, HIPAA, PCI DSS).

Early detection enables organizations to mitigate these risks by:

• Promptly revoking compromised credentials.

• Enhancing authentication security (e.g., multi-factor authentication).

• Conducting targeted user awareness training.

• Strengthening monitoring and response capabilities.

Examples

Real-world examples illustrating the use of the "Search Closed Sources" technique include:

• APT29 (Cozy Bear) and SolarWinds Attack:

  • Attackers gained access to private GitHub repositories containing proprietary source code and internal documentation, enabling them to compromise the SolarWinds Orion software supply chain.

  • Tools used: compromised credentials, GitHub access, custom malware implants.

  • Impact: widespread supply chain compromise affecting thousands of organizations, including U.S. government agencies.

• FIN4 Campaign Targeting Financial Institutions:

  • Attackers infiltrated subscription-based financial databases and private investor forums to gather insider information and financial data.

  • Tools used: spear phishing, credential theft, private forum infiltration.

  • Impact: insider trading schemes, financial losses, regulatory scrutiny for targeted organizations.

• Operation Aurora (Google and Adobe Attacks):

  • Attackers leveraged compromised credentials to access internal documentation and source code repositories, gathering sensitive intellectual property.

  • Tools used: credential harvesting malware, targeted phishing, internal source code repository access.

  • Impact: theft of intellectual property, reputational damage, significant remediation costs.

• Corporate Espionage via Private Slack Channels:

  • Attackers infiltrated private Slack workspaces using leaked credentials to access confidential internal discussions, strategic plans, and sensitive documents.

  • Tools used: credential stuffing, Slack infiltration, data exfiltration tools.

  • Impact: loss of competitive advantage, damage to organizational trust, and potential legal actions.

These examples highlight the diverse contexts, tools, and impacts associated with the "Search Closed Sources" technique, underscoring the importance of robust detection and response capabilities.