CVEvulnerability
CVE-2020-27632
7.5 HIGH
Official page ↗
- Status
- Modified
- Published
- 2021-03-10
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CVSS 2.0 ([email protected])
- 5.0 MEDIUM — AV:N/AC:L/Au:N/C:N/I:P/A:N
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.
Affected configurations
• siemens simatic mv420 firmware (< 7.0.6)
• siemens simatic mv440 firmware (< 7.0.6)
References
- https://cert-portal.siemens.com/productcert/pdf/ssa-599268.pdf Vendor Advisory
- https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01 www.cisa.gov
- https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/ www.forescout.com
- https://cert-portal.siemens.com/productcert/pdf/ssa-599268.pdf Vendor Advisory
- https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01 www.cisa.gov
- https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/ www.forescout.com