CVE-2017-17023: The Sophos UTM VPN endpoint interacts with client software provided by NPC Engineering (www.ncp-e.com). The affected client software, "Sophos IPSec Cl...

Description

The Sophos UTM VPN endpoint interacts with client software provided by NPC Engineering (www.ncp-e.com). The affected client software, "Sophos IPSec Client" 11.04 is a rebranded version of NCP "Secure Entry Client" 10.11 r32792. A vulnerability in the software update feature of the VPN client allows a man-in-the-middle (MITM) or man-on-the-side (MOTS) attacker to execute arbitrary, malicious software on a target user's computer. This is related to SIC_V11.04-64.exe (Sophos), NCP_EntryCl_Windows_x86_1004_31799.exe (NCP), and ncpmon.exe (both Sophos and NCP). The vulnerability exists because: (1) the VPN client requests update metadata over an insecure HTTP connection; and (2) the client software does not check if the software update is signed before running it.

Metrics

EPSS Probability

0.61%

44.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-345

Affected Software

Vendor	Product	Versions	Update
Ncp-E	Ncp Secure Entry Client	10.11	32792
Sophos	Ipsec Client	11.04	—

References

Timeline

Published: Apr 9, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-17023?

The Sophos UTM VPN endpoint interacts with client software provided by NPC Engineering (www.ncp-e.com). The affected client software, "Sophos IPSec Client" 11.04 is a rebranded version of NCP "Secure Entry Client" 10.11 r32792. A vulnerability in the software update feature of the VPN client allows a man-in-the-middle (MITM) or man-on-the-side (MOTS) attacker to execute arbitrary, malicious software on a target user's computer. This is related to SIC_V11.04-64.exe (Sophos), NCP_EntryCl_Windows_x86_1004_31799.exe (NCP), and ncpmon.exe (both Sophos and NCP). The vulnerability exists because: (1) the VPN client requests update metadata over an insecure HTTP connection; and (2) the client software does not check if the software update is signed before running it.

How severe is CVE-2017-17023?

Severity scoring for CVE-2017-17023 is pending analysis. The EPSS model estimates a 0.61% probability of exploitation in the next 30 days.

How do I fix CVE-2017-17023?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.