CVE-2017-20203

Summary

NetSarang Xmanager Enterprise 5.0 Build 1232, Xmanager 5.0 Build 1045, Xshell 5.0 Build 1322, Xftp 5.0 Build 1218, and Xlpd 5.0 Build 1220 contain a malicious nssock2.dll that implements a multi-stage, DNS-based backdoor. The dormant library contacts a C2 DNS server via a specially crafted TXT record for a month‑generated domain. After receiving a decryption key, it then downloads and executes arbitrary code, creates an encrypted virtual file system (VFS) in the registry, and grants the attacker full remote code execution, data exfiltration, and persistence. NetSarang released builds for each product line that remediated the compromise: Xmanager Enterprise Build 1236, Xmanager Build 1049, Xshell Build 1326, Xftp Build 1222, and Xlpd Build 1224. Kaspersky Lab identified an instance of exploitation in the wild in August 2017.

Affected Software

VendorProductVersion RangeStatus
NetSarang Computer, Inc.Xmanager Enterprise5.0 Build 1232affected
NetSarang Computer, Inc.Xmanager5.0 Build 1045affected
NetSarang Computer, Inc.Xshell5.0 Build 1322affected
NetSarang Computer, Inc.Xftp5.0 Build 1218affected
NetSarang Computer, Inc.Xlpd5.0 Build 1220affected

Weaknesses

  • CWE-506: CWE-506 Embedded Malicious Code

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: total

References