Cleo file transfer zero-days exploited by Clop for data theft

Updates on Dec 17, 2024

Summary

Two unauthenticated file-write bugs in Cleo Harmony, VLTrader and LexiCom managed file transfer software (CVE-2024-50623 and CVE-2024-55956) were mass-exploited in December 2024 to plant a Java backdoor and steal data. Huntress saw exploitation from 2024-12-03 against systems already patched to 5.8.0.21; Cleo shipped 5.8.0.24 for the second bug. The Clop ransomware gang claimed the attacks. Added to the CISA KEV catalog on 2024-12-13, 2024-12-17. CISA lists known use in ransomware campaigns.

Advisories5

• Cleo Product Security Update: CVE-2024-55956Cleo · Dec 14, 2024
• Cleo advisory: CVE-2024-50623Cleo
• NVD: CVE-2024-50623NVD · Oct 27, 2024
• NVD: CVE-2024-55956NVD · Dec 13, 2024
• CISA Known Exploited Vulnerabilities CatalogCISA · Dec 13, 2024