Description
In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.
References (3)
Core 3
Core References
Various Sources
https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/
Third Party Advisory, US Government Resource
https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01
Vendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-599268.pdf
Scores
CVSS v3
7.5
EPSS
0.0038
EPSS Percentile
59.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Details
Status
published
Products (2)
siemens/simatic_mv420_firmware
< 7.0.6
siemens/simatic_mv440_firmware
< 7.0.6
Published
Mar 10, 2021
Tracked Since
Feb 18, 2026