Vulnerability in Netsarang Computer, Inc. Xftp
CVE-2017-20203
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.
EPSS: 0.006 (46.2th percentile) — read the EPSS interpretation.
Affected products
- Netsarang Computer, Inc. Xftp — versions 5.0 Build 1218
- Netsarang Computer, Inc. Xlpd — versions 5.0 Build 1220
- Netsarang Computer, Inc. Xmanager — versions 5.0 Build 1045
- Netsarang Computer, Inc. Xmanager Enterprise — versions 5.0 Build 1232
- Netsarang Computer, Inc. Xshell — versions 5.0 Build 1322
Weakness classification (CWE)
Public proof-of-concept exploits
References
- disclosure@vulncheck.com (vendor-advisory, patch)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2017-20203?
- CVE-2017-20203 is a vulnerability in Netsarang Computer, Inc. Xftp, classified under CWE-506. Published 2025-10-09.
- Is CVE-2017-20203 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.