Reflective Code Loading

Reflective Code Loading [T1620]

Information

• Name: Reflective Code Loading

• ID: T1620

• Tactics: TA0005

Introduction

Reflective Code Loading is an execution technique categorized within the MITRE ATT&CK framework (Technique ID: T1620). It involves dynamically loading and executing code directly into memory without writing files or artifacts to disk. Attackers leverage this technique to evade traditional detection mechanisms and forensic analysis, as it significantly reduces their digital footprint. Reflective loading is commonly associated with fileless malware, advanced persistent threats (APTs), and sophisticated intrusion campaigns.

Deep Dive Into Technique

Reflective Code Loading enables attackers to load executable code directly into memory without leaving disk-based artifacts. This is achieved through a method known as reflective DLL injection or reflective PE loading. The core concept involves:

• Loading binaries or libraries directly into memory space of a running process.

• Resolving required API calls dynamically at runtime without relying on the operating system loader.

• Employing custom loaders, shellcode, or scripting languages to facilitate reflective loading.

Technical details include:

• Reflective DLL Injection:

  • Attackers inject a DLL into a running process memory without using standard Windows API calls like LoadLibrary.

  • A reflective loader function within the DLL resolves all required imports and relocations internally.

  • The injected DLL executes entirely from memory, avoiding disk detection.

• Process Hollowing:

  • Attackers start a legitimate process in a suspended state, then replace its memory content with malicious code.

  • The legitimate process is then resumed, executing malicious code while appearing benign.

• Memory Module Techniques:

  • Attackers load Portable Executable (PE) files directly into memory without writing them to disk.

  • Custom loaders handle PE header parsing, section loading, relocations, and imports dynamically.

Common tools and frameworks used include:

• Metasploit Framework (Reflective DLL Injection modules)

• PowerSploit (Invoke-ReflectivePEInjection)

• Cobalt Strike's Beacon payloads

• Empire Framework (PowerShell-based reflective loaders)

When this Technique is Usually Used

Reflective Code Loading is frequently utilized in various attack stages and scenarios, including:

• Initial Access and Execution:

  • Attackers deliver payloads via phishing emails or malicious websites that execute directly in memory.

  • Fileless malware campaigns leverage reflective loading to minimize disk artifacts.

• Privilege Escalation and Persistence:

  • Malicious actors inject reflective code into privileged processes to escalate privileges or maintain persistence without leaving traces on disk.

• Defense Evasion:

  • Reflective loading is commonly employed to bypass traditional antivirus and endpoint protection systems, as it avoids file-based detections and signature-based scanning.

• Lateral Movement:

  • Attackers inject reflective payloads into running processes on remote systems to move laterally undetected within the network.

• Command and Control (C2):

  • Reflective payloads facilitate stealthy communication with attacker-controlled servers, minimizing detection by network monitoring solutions.

How this Technique is Usually Detected

Detection of Reflective Code Loading is challenging but achievable through comprehensive monitoring and advanced detection mechanisms:

• Endpoint Detection and Response (EDR):

  • Monitor process memory allocations, process injection activities, and unusual API calls.

  • Detect suspicious threads or memory regions within legitimate processes.

• Behavioral Analysis and Heuristics:

  • Identify abnormal process behaviors, such as unexpected memory allocations or injection into sensitive processes.

  • Detect anomalous API usage patterns (e.g., VirtualAllocEx, WriteProcessMemory, CreateRemoteThread).

• Memory Scanning and Forensics:

  • Perform memory scans for reflective loader signatures or suspicious memory regions.

  • Utilize memory forensic tools (e.g., Volatility, Rekall) to analyze memory dumps for injected code.

• Sysmon and Event Logging:

  • Configure Sysmon to log process creations, memory injection events, and suspicious thread creations.

  • Analyze Windows event logs for unusual process injection activity.

• Network Detection:

  • Monitor network traffic for anomalous outbound connections possibly initiated by injected code.

  • Employ Network Intrusion Detection Systems (NIDS) to detect C2 traffic patterns associated with reflective payloads.

Specific Indicators of Compromise (IoCs):

• Suspicious process injection events logged by Sysmon (Event ID 8: CreateRemoteThread)

• Unusual memory allocations and permissions (RWX memory segments)

• Presence of known reflective loader signatures or shellcode patterns in memory dumps

• Anomalous API call sequences detected by behavioral analytics tools

Why it is Important to Detect This Technique

Early detection of Reflective Code Loading is critical due to its potential impacts on systems and networks:

• Stealth and Persistence:

  • Reflective loading leaves minimal traces on disk, allowing attackers to remain undetected for extended periods.

  • Persistent memory-resident threats can compromise systems indefinitely without detection.

• Advanced Threats and Espionage:

  • Frequently used by advanced persistent threats (APTs) for espionage, data theft, and long-term presence within targeted environments.

• Evasion of Security Controls:

  • Traditional antivirus and signature-based detection solutions often fail to detect reflective loading, emphasizing the need for advanced detection methodologies.

• System Integrity and Stability:

  • Injected malicious code can compromise process integrity, leading to instability, crashes, or unauthorized access to sensitive data.

• Data Exfiltration and Damage:

  • Reflective payloads can facilitate data exfiltration, ransomware deployment, or system sabotage, resulting in severe operational and financial impacts.

Early detection and response can:

• Limit attacker dwell time and reduce potential damage.

• Improve organizational security posture and resilience against advanced threats.

• Facilitate faster incident response and remediation efforts.

Examples

Real-world examples of Reflective Code Loading include:

• Cobalt Strike Beacon:

  • Widely used penetration testing and red team tool employing reflective DLL injection.

  • Attackers frequently abuse this tool to inject payloads into memory for command and control, lateral movement, and data exfiltration.

• PowerSploit Framework (Invoke-ReflectivePEInjection):

  • PowerShell-based framework allowing attackers to load PE files directly into memory.

  • Commonly leveraged in fileless malware attacks and advanced intrusion scenarios.

• Metasploit Framework Reflective DLL Injection:

  • Provides modules for reflective DLL injection, enabling attackers to inject payloads into memory without disk artifacts.

  • Used extensively in penetration testing and malicious intrusion activities.

• FIN7 APT Group:

  • Known to utilize reflective code loading to deploy payloads stealthily into target environments, bypassing traditional detection mechanisms.

  • Associated with attacks on financial institutions, retail, and hospitality sectors.

• Operation Cobalt Kitty:

  • Threat actors employed reflective DLL injection techniques to evade detection and persistently compromise telecommunications and technology companies.

  • Demonstrated sophisticated reflective loading techniques combined with lateral movement and espionage activities.

These examples highlight the prevalence and impact of Reflective Code Loading across different threat actors and attack scenarios, underscoring the importance of detection and mitigation strategies.