Description
An issue was discovered in HCC Nichestack 3.0. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. (Proper ISN generation should aim to follow at least the specifications outlined in RFC 6528.)
References (4)
Core 4
Core References
Product x_refsource_misc
https://www.hcc-embedded.com
Mitigation, Third Party Advisory x_refsource_confirm
https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdf
Mitigation, Third Party Advisory x_refsource_misc
https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/
Third Party Advisory, US Government Resource third-party-advisory
x_refsource_cert-vn
https://www.kb.cert.org/vuls/id/608209
Scores
CVSS v3
9.1
EPSS
0.0205
EPSS Percentile
78.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Details
CWE
CWE-330
Status
published
Products (3)
hcc-embedded/nichestack
3.0
siemens/sentron_3wa_com190_firmware
< 2.0.0
siemens/sentron_3wl_com35_firmware
< 1.2.0
Published
Aug 19, 2021
Tracked Since
Feb 18, 2026