Process injection is a sophisticated and widely used technique in cybersecurity where an attacker injects and executes malicious code within the address space of a legitimate, running process. By leveraging the trusted context of these legitimate processes, adversaries can evade detection, escalate privileges, and maintain persistence on a compromised system.
How Process Injection Works
• Target Selection: The attacker identifies a running process, often one with elevated privileges or that is allow-listed by security tools (e.g., svchost.exe, rundll32.exe).
• Memory Manipulation: The attacker allocates memory in the target process and writes their malicious code into this space using system APIs (e.g., OpenProcess(), VirtualAllocEx(), WriteProcessMemory()).
• Execution Trigger: The attacker initiates execution of the injected code, often by creating a new thread in the target process (CreateRemoteThread()) or hijacking an existing thread.
• Stealth and Evasion: The malicious code runs under the privileges and identity of the legitimate process, making it difficult for security tools to detect the intrusion since the process itself appears normal.
Why Attackers Use Process Injection
• Defense Evasion: Since the code runs inside a trusted process, it avoids detection by antivirus and endpoint security solutions that typically monitor new or untrusted processes.
• Privilege Escalation: If the targeted process has higher privileges, the injected code inherits these, allowing attackers to perform actions that would otherwise be restricted.
• Persistence: Attackers can maintain long-term access by hiding their code within processes that are always running or are critical to the operating system.
• Lateral Movement: Process injection can facilitate movement across a network by leveraging the access rights of the compromised process.
Detection and Prevention
• Behavioral Monitoring: Watch for unusual memory allocations, thread creations, and process manipulations.
• Memory Protection: Use security solutions that monitor in-memory activity, not just files on disk.
• Access Controls: Restrict permissions to prevent unauthorized process manipulation.
• Endpoint Detection and Response (EDR): Advanced tools can detect suspicious process injection patterns and respond in real time.