PEB masquerading is a stealth technique used by malware to disguise itself as a legitimate system process. It manipulates the Process Environment Block (PEB), a data structure in Windows operating systems that stores information about running processes. By altering fields such as the process name or image path within the PEB, malicious software can evade detection tools and security analysts, as it appears to be a trusted or benign process. This method is particularly effective against security solutions that rely on process names or attributes for identification, making it a favored tactic for advanced persistent threats and sophisticated malware campaigns.