MicroStealer is a fully functional infostealer spreading rapidly while evading traditional security detections. ANY.RUN researchers identified the malware in 40+ sandbox sessions within a month despite low public awareness. Distribution leverages compromised or impersonated accounts. The critical insight: a dangerous gap exists between actual prevalence and detection visibility—conventional tools miss this threat entirely, leaving organizations exposed. The analysis underscores the value of sandbox-based monitoring and behavioral analysis for identifying emerging infostealers before widespread distribution. Early detection and containment remain essential as the threat proliferates undetected.