Hunt: Snowblind – The Invisible Hand of Secret Blizzard

A sophisticated attacker, potentially the “Secret Blizzard” group, has gained access to the network and is actively attempting to establish persistence, evade detection, escalate privileges, and collect sensitive data. They are likely using custom malware with advanced anti-analysis capabilities and are targeting specific systems and data.

Name:
Hunt: Snowblind – The Invisible Hand of Secret Blizzard

TTP:
T1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control, T1547.001 Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder, T1543.003 Create or Modify System Process: Windows Service, T1555 Credentials from Password Stores, T1005 Data from Local System, T1562.001 Impair Defenses: Disable or Modify Tools, T1070.001 Indicator Removal: Clear Windows Event Logs, T1027.002 Obfuscated Files or Information: Software Packing, T1082 System Information Discovery

Hypothesis:

A sophisticated attacker, potentially the “Secret Blizzard” group, has gained access to the network and is actively attempting to establish persistence, evade detection, escalate privileges, and collect sensitive data. They are likely using custom malware with advanced anti-analysis capabilities and are targeting specific systems and data.

Campaign Type:
Hybrid

Data Sources:

  • Endpoint Security Logs (EDR)
  • Windows Event Logs (System, Security, Application)
  • Network Traffic Logs (Firewall, IDS/IPS, PCAP)
  • Registry Logs
  • File System Logs
  • Memory Forensics Data

Tools:

  • Security Monitoring Tools:

    • Sysmon: For detailed host-level logging of process creation, network connections, file system activity, and more.
       
    • SIEM Platform: For centralizing logs, correlating events, and conducting security analysis. Examples include Splunk, QRadar, Azure Sentinel, and ELK stack.
       

  • Attack Emulation Tools:

    • Atomic Red Team: For executing atomic tests that emulate specific adversary tactics and techniques.
    • Metta: For running automated attack simulations and generating representative security events.

  • Analysis Tools:

    • YARA: For creating and applying rules to identify and classify malware based on patterns and characteristics.
    • SIGMA: For writing generic signatures that can be translated into SIEM-specific queries for threat detection.
    • Volatility: For conducting memory forensics and analyzing runtime system data.
    • Wireshark: For capturing and analyzing network traffic to identify suspicious communication patterns.

  • Other Tools:

    1. Mimikatz: For extracting credentials and other sensitive information from memory.
    2. PsExec: For executing commands on remote systems.
    3. Process Monitor: For monitoring and analyzing real-time system activity, including process creation, file system access, and registry modifications.

Scenario:

Initial Access: The attacker likely gained initial access through a spear-phishing email containing a malicious attachment or a link to a compromised website exploiting a zero-day vulnerability (T1190 – Exploit Public-Facing Application).

Defense Evasion:

  • The attacker employs various techniques to evade detection, including disabling or modifying security tools (T1562.001), packing malware (T1027.002), and clearing event logs (T1070.001).
  • They may also use obfuscation techniques to hide their malicious code and activities (T1027).

Persistence:

  • The attacker establishes persistence by creating or modifying system processes (T1543) and using boot or logon autostart execution mechanisms (T1547).
  • This could involve creating malicious Windows services (T1543.003) or modifying registry run keys (T1547.001).

Privilege Escalation:

  • The attacker attempts to escalate privileges by abusing elevation control mechanisms (T1548), such as bypassing User Account Control (UAC) (T1548.002).
  • They may exploit vulnerabilities or use social engineering techniques to gain higher-level access.

Discovery:

  • The attacker performs system information discovery (T1082) to gather information about the network, systems, and users.
  • This helps them identify valuable targets and plan their next steps.

Collection:

  • The attacker collects sensitive data from the local system (T1005), including credentials from password stores (T1005.003).
  • They may also target specific files or databases containing valuable information.

Lateral Movement:

  • The attacker moves laterally within the network to compromise additional systems and expand their access (TA0008).
  • They may use various techniques, such as exploiting remote services (T1210) or using valid accounts (T1078).

Exfiltration:

  • The attacker exfiltrates the collected data to a remote server under their control (TA0010).
  • They may use various methods, such as encrypting and transferring data over common protocols (T1041) or using covert channels (T1071).

Hunting Strategy:

  1. Data Collection and Correlation: Collect data from the identified sources and correlate events across different logs. Look for suspicious patterns, such as:

    • Unusual process executions, especially those related to system administration or security tools.
    • Modifications to registry keys associated with autostart execution or system services.
    • Attempts to clear event logs or disable security tools.
    • Network connections to known malicious IP addresses or domains.
    • Suspicious file activity, such as creation, modification, or deletion of files in sensitive locations.

  2. Anomaly Detection: Analyze the data for outliers and anomalies that deviate from normal behavior. This could include:

    • Unexpected spikes in network traffic or system resource usage.
    • Unusual login attempts or account activity.
    • Processes running with elevated privileges without legitimate reasons.
    • Files with abnormal sizes, timestamps, or hashes.

  3. Threat Intelligence Integration: Leverage threat intelligence feeds and reports to identify known indicators of compromise (IOCs) associated with “Secret Blizzard” or similar APT groups. Look for:

    • Specific malware hashes or filenames.
    • Command-and-control (C2) infrastructure (IP addresses, domains, URLs).
    • Attacker tools or techniques previously used by the group.

  4. YARA/SIGMA Rule Development: Develop custom YARA or SIGMA rules based on the identified TTPs and IOCs to proactively scan for malicious activity.

  5. Memory Forensics: Utilize memory forensics techniques to analyze running processes and identify hidden or obfuscated malware.

  6. Endpoint Analysis: Conduct in-depth analysis of suspicious endpoints to identify malware, persistence mechanisms, and other artifacts.

  7. Network Traffic Analysis: Analyze network traffic for suspicious communication patterns, C2 traffic, and data exfiltration attempts.

False Positive Consideration:

  • Legitimate system administration activities may trigger some of the detection rules.
  • Software updates or security patches may generate events that resemble malicious activity.
  • Users may inadvertently disable security tools or clear event logs.

Recommendations:

  • MITRE Engage:

    • Active Defense: Implement proactive measures to disrupt attacker activities, such as decoy systems (T1603) or honeyfiles (T1602).
    • Threat Intelligence: Continuously gather and analyze threat intelligence to stay informed about the latest TTPs and IOCs.

  • MITRE D3fend:

    • Hardening: Harden systems and applications by disabling unnecessary services, implementing least privilege principles, and applying security patches.
    • Application Control: Implement application control solutions to prevent the execution of unauthorized software.
    • Endpoint Detection and Response (EDR): Deploy EDR solutions to monitor endpoint activity, detect malicious behavior, and respond to threats in real-time.
    • Network Security Monitoring: Implement network security monitoring tools to detect and analyze suspicious network traffic.
    • Security Awareness Training: Educate users about phishing attacks, social engineering techniques, and other security threats.

Step-by-Step Guide to Emulate a Threat Hunt:

  1. Prepare the Environment:

    • Set up a lab environment with Windows machines and relevant security monitoring tools (Sysmon, SIEM, etc.).
    • Enable auditing policies for key events (process creation, file system activity, registry modifications, etc.).
    • Configure a centralized log management system to collect and store security events.

  2. Emulate the Attack Techniques:

    • Use tools like Atomic Red Team or Metta to emulate the TTPs associated with “Secret Blizzard” or similar APT groups.
    • Execute commands and actions that simulate disabling security tools, clearing event logs, establishing persistence, escalating privileges, and collecting data.

  3. Emulate Post-Compromise Activities:

    • Simulate lateral movement by using tools like Mimikatz or PsExec to access other systems.
    • Emulate data exfiltration by transferring files to a remote server using common protocols or covert channels.

  4. Collect and Analyze Logs:

    • Collect the generated security event logs from the centralized log management system.
    • Use analysis tools (SIEM, log analysis platforms) to search for events related to the emulated attack techniques.
    • Filter events based on relevant criteria (process names, command-line parameters, network connections, etc.).

  5. Refine Detections:

    • Analyze the collected logs to identify patterns and refine detection rules.
    • Create custom YARA or SIGMA rules based on the observed events.
    • Document the analysis and findings to improve future threat hunting efforts.

D3 Diagram:

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