Process hollowing is a technique used by cybercriminals to hide and execute malicious code in the address space of a legitimate process. By replacing the code of a legitimate process with a malicious payload and running it as if it were part of the original process, attackers can avoid detection by security tools and operate covertly on the system.
The hollowing process follows these steps:
Replacement: Attackers start by creating a legitimate process, usually by calling the CreateProcess function in Windows. Then they replace the code of this process with a malicious payload. This is accomplished by manipulating the process memory, specifically the part that contains the executable code.
Execution: Once modified, the process is launched and executes the malicious code. From the point of view of the operating system and any security software, it looks like a legitimate process is being executed. This allows attackers to carry out their malicious actions without arousing suspicion.
Invisibility: One of the main advantages of the hollowing process is the ability to hide malicious activity in the form of an innocent process. By running malicious code in the address space of a legitimate process, attackers can bypass traditional security measures based on detecting suspicious or malicious processes. This includes antivirus programs, intrusion detection systems, and behavioral analysis tools.
Tips for prevention
To protect against hollowing attacks, it is important to implement security precautions and best practices. Here are some tips to consider:
Monitoring tools: Use process monitoring tools that can detect any anomalies in process behavior or changes in their memory. These tools can help detect potential process hollowing attempts and alert administrators for further investigation.
Digital signature of the code: Regularly check the digital code signature and other indicators of legitimacy for processes and their modules. A digital signature allows you to confirm that the code has not been tampered with and that it comes from a trusted source.
Endpoint protection: Implement powerful endpoint security solutions that can detect and prevent process hollowing techniques. Endpoint protection solutions use a variety of detection mechanisms, including behavioral analysis, heuristics, and machine learning, to detect and block malicious activities.
Update management: Keep software and operating systems up to date with the latest security patches. Vulnerabilities in software can often be exploited by attackers to gain access to processes and perform hollowing.
User education: Educate users about potential threats and encourage them to exercise caution when opening email attachments, downloading files, or visiting suspicious websites. By creating a culture of cybersecurity awareness, users can become an additional line of defense against hollowing attacks.