Passguard is a supply chain security platform that detects infostealer malware infections on supplier and vendor devices. The platform monitors exclusive stealer marketplaces and criminal forums where compromised device data and stolen sessions are traded, providing visibility into supplier compromises that traditional vendor risk tools miss. The platform scans key suppliers to detect compromised devices and exposed sessions, including those in censored stealer logs where company names may be hidden but supplier connections are visible. It provides real-time visibility into supplier infections, with new compromises appearing within hours of being listed on criminal marketplaces. Passguard operates without requiring direct access to supplier systems, instead monitoring dark web and underground marketplaces for evidence of supplier device infections. The platform identifies when supplier sessions appear in stealer logs, even when the customer's own data is censored, allowing security teams to detect and respond to supply chain risks before attackers can pivot laterally into their environment. The service includes supplier notification capabilities to alert vendors of detected compromises. It provides visibility beyond traditional dark web monitoring of old credential breaches, focusing specifically on active infostealer infections affecting the supply chain.