Portable Executable Injection
Portable Executable Injection [T1055.002]
Last updated
Portable Executable Injection [T1055.002]
Last updated
Name: Portable Executable Injection
ID: T1055.002
Tactics: ,
Technique:
Portable Executable Injection (T1055.002) is a sub-technique of Process Injection (T1055) within the MITRE ATT&CK framework. It involves injecting malicious code directly into a legitimate Portable Executable (PE) file, typically used by Windows operating systems. Attackers leverage this method to evade defenses, maintain persistence, escalate privileges, and execute malicious payloads under the disguise of legitimate processes. This technique is particularly effective because it allows attackers to exploit trusted system binaries, making detection and attribution challenging.
Portable Executable Injection involves embedding malicious code or payloads directly into PE files, which include executable (.exe), dynamic-link library (.dll), or system driver (.sys) files. Attackers manipulate these files to execute unauthorized code without creating new or suspicious processes. Common technical methods include:
PE File Modification:
Attackers modify executable headers or sections within PE files to insert malicious code.
Malicious code can be appended to unused sections or injected into existing sections by overwriting or expanding them.
Hollowing Techniques (Process Hollowing):
Attackers start legitimate processes in a suspended state.
Original code in memory is replaced with malicious code before the process is resumed, effectively running attacker-controlled code under the guise of a legitimate process.
DLL Injection via PE Modification:
Malicious DLL files are injected into legitimate processes by modifying PE headers or import tables.
The legitimate process unknowingly loads and executes malicious DLLs during initialization.
Entry Point Manipulation:
Attackers alter the entry point of a PE file to redirect execution flow to malicious code.
The malicious code executes first, then optionally returns control to the legitimate code to avoid suspicion.
Attackers often use specialized tools or scripts to automate PE injection, reducing the complexity and time required to execute these attacks. Commonly used tools include custom scripts, open-source frameworks, and malware families specifically designed for stealthy PE injection.
Portable Executable Injection is frequently employed by attackers during various phases of the cyber kill-chain, including:
Initial Access and Execution:
Attackers embed malicious payloads in legitimate software installers or executables distributed via phishing emails, software downloads, or compromised websites.
Persistence:
Malicious code injected into legitimate system binaries or processes persists across system reboots, providing attackers continuous access.
Privilege Escalation:
Injecting malicious code into processes with higher privileges allows attackers to escalate their privileges to administrative or system-level rights.
Defense Evasion:
Injecting into trusted system binaries enables attackers to evade antivirus, endpoint detection and response (EDR), and other security tools that trust legitimate processes.
Lateral Movement:
Injected malicious PE files can be propagated through internal networks, allowing attackers to move laterally while minimizing detection risk.
Detection of Portable Executable Injection usually involves a combination of behavioral analysis, memory inspection, and file integrity monitoring. Common detection methods include:
Behavioral Detection:
Monitoring process creation, suspension, and resumption events.
Detecting unusual process behaviors, such as unexpected memory allocations or suspicious API calls.
Memory Analysis:
Performing memory scans to detect discrepancies between in-memory PE images and their corresponding files on disk.
Using tools like Volatility Framework, Process Hacker, or Process Monitor to inspect running processes and their memory regions.
File Integrity Monitoring (FIM):
Monitoring PE files for unauthorized changes to headers, sections, or entry points.
Employing tools like Tripwire, OSSEC, or built-in Windows features (Windows Defender Application Control, AppLocker) to detect unauthorized file modifications.
Endpoint Detection and Response (EDR) Solutions:
Advanced EDR solutions detect suspicious injection activities by analyzing process behaviors, API calls, and memory manipulations in real-time.
Indicators of Compromise (IoCs):
Suspicious file hashes or modified timestamps on critical system PE files.
Unusual DLLs loaded by legitimate processes.
Unexpected outbound network connections from legitimate system processes.
Detecting Portable Executable Injection is crucial due to its stealthy nature and potential severe impacts on systems and networks. Early detection is critical because:
Defense Evasion and Stealth:
Attackers leverage trusted processes to hide their malicious activities, making detection challenging without specialized monitoring.
Early detection prevents attackers from embedding themselves deeply within legitimate system processes.
Persistence and Long-Term Compromise:
Injected PE files can persistently execute malicious code, enabling prolonged attacker presence in a compromised environment.
Early detection limits attacker dwell time and reduces potential damage.
Privilege Escalation and Credential Theft:
Attackers frequently inject malicious code into high-privilege processes, facilitating privilege escalation and credential theft.
Timely detection prevents attackers from moving laterally within the network and accessing sensitive resources.
System Stability and Integrity:
Malicious PE injections can destabilize critical system processes or cause unexpected system behavior, impacting business operations.
Early detection preserves system integrity and reliability.
Data Exfiltration and Ransomware Deployment:
Injected code often serves as a foothold for further malicious activities, including data theft, ransomware deployment, or sabotage.
Detecting injection early helps mitigate severe operational, financial, and reputational impacts.
Real-world examples demonstrating Portable Executable Injection include:
TrickBot Malware:
TrickBot employs PE injection methods such as process hollowing to inject malicious payloads into legitimate Windows processes (e.g., svchost.exe).
Attackers use TrickBot to deliver secondary payloads, including ransomware (Ryuk, Conti), leading to large-scale data breaches and operational disruptions.
Dridex Banking Trojan:
Dridex uses process hollowing techniques to inject malicious code into legitimate processes, enabling credential theft and financial fraud.
Attackers leverage Dridex-infected systems for lateral movement and subsequent ransomware deployment.
Cobalt Strike Framework:
Attackers frequently use Cobalt Strike Beacon payloads injected into legitimate processes via PE injection techniques.
Cobalt Strike facilitates command-and-control (C2) communications, privilege escalation, lateral movement, and data exfiltration.
Ursnif Banking Trojan:
Ursnif injects malicious DLLs into legitimate processes, allowing attackers to steal credentials, banking information, and sensitive data.
Ursnif infections often result in significant financial losses and compromised sensitive information.
APT29 (Cozy Bear) Campaigns:
APT29, associated with nation-state espionage, uses PE injection techniques to embed malicious payloads into legitimate applications and evade detection.
These attacks have targeted government entities, research institutions, and critical infrastructure with significant geopolitical impacts.
In each example, attackers successfully leveraged Portable Executable Injection to bypass defenses, maintain persistence, escalate privileges, and achieve their malicious objectives. Early detection and response are essential to mitigating the impacts of these advanced threats.