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CVE-2017-20203

30
FAUCET Score

CVE-2017-20203 describes a critical supply chain compromise affecting NetSarang Xmanager, Xshell, Xftp, and Xlpd products, where a malicious nssock2.dll library implemented a multi-stage, DNS-based backdoor. This backdoor, rated 9.3 Critical, allowed for remote code execution, data exfiltration, and persistence by contacting a C2 server via DNS TXT records to download and execute arbitrary code. Kaspersky Lab observed active exploitation in August 2017, although public exploit code and community discussion remain minimal. Patched versions were released by NetSarang to remediate this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
NetSarang Computer, Inc.Xftp
5.0 Build 1218CNA affecteddefault unaffected
NetSarang Computer, Inc.Xlpd
5.0 Build 1220CNA affecteddefault unaffected
NetSarang Computer, Inc.Xmanager Enterprise
5.0 Build 1232CNA affecteddefault unaffected
NetSarang Computer, Inc.Xmanager
5.0 Build 1045CNA affecteddefault unaffected
NetSarang Computer, Inc.Xshell
5.0 Build 1322CNA affecteddefault unaffected

CVSS Data

CVSS version used by this source: 4.0

9.3CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
ACTIVE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
NONE
SS Confidentiality
HIGH
SS Integrity
HIGH
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.62%
Probability of exploitation in next 30 days
EPSS Percentile
46.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0062 is in the 52nd percentile among its peer group of 836 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.8 Bluesky, 0.5 Mastodon, and 1.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

securelist.com / shadowpad-in-corporate-networks/81432
usa.kaspersky.com / about/press-releases/shadowpad-attackers-hid-backdoor-in-software-used-by-hundreds-of-large-companies-worldwide
web.archive.org / web/20181022035109/https://www.netsarang.com/news/security_exploit_in_july_18_2017_build.html
vulncheck.com / advisories/netsarang-malicious-backdoor-supply-chain-compromise