Security readout for executives and security teams
Plain-English summary
Some Siemens building-control and embedded networking products may use predictable TCP connection numbers. That can let a network attacker interfere with or impersonate TCP sessions, affecting integrity or availability rather than exposing data directly.
Executive priority
Treat as a moderate operational technology risk. It is not described as data theft or actively exploited, but affected building-control systems may support important facility operations and should be upgraded or isolated during normal maintenance windows.
Technical view
CVE-2020-28388 is CWE-342: TCP initial sequence numbers are derived from insufficient randomness. The listed Siemens APOGEE, TALON, Nucleus, and PLUSCONTROL products could allow session hijacking or spoofing of future TCP connections. CVSS v3.1 is 6.5, network-accessible, low complexity, unauthenticated, with official remediation indicated.
Likely exposure
Exposure is limited to environments running the named Siemens products and affected versions, especially building automation or embedded systems reachable over IP networks. Nucleus Source Code and PLUSCONTROL are listed as all versions affected in the provided bundle.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. The CVSS temporal vector indicates proof-of-concept exploit maturity, so treat this as plausible but not confirmed active exploitation.
Researcher notes
The key condition is predictable TCP ISNs, not application authentication bypass. Validation should focus on product/version exposure and network adjacency. Avoid assuming exploitability across all deployments; session spoofing feasibility depends on topology, traffic visibility, and protocol behavior.
Mitigation direction
- Inventory affected Siemens APOGEE, TALON, Nucleus, and PLUSCONTROL deployments.
- Upgrade products to versions outside the affected ranges where fixed versions are listed.
- Check Siemens ProductCERT advisories for product-specific remediation and unsupported all-version products.
- Reduce unnecessary network reachability to affected controllers and embedded systems.
- Prioritize remediation where affected devices communicate across untrusted or routed networks.
Validation and detection
- Confirm exact product names and firmware/software versions against the affected version list.
- Check whether affected devices are reachable over TCP from user, vendor, or external networks.
- Review Siemens ProductCERT advisories for remediation status per product line.
- Validate that upgraded systems report fixed versions after maintenance.
- Monitor for unexpected TCP session resets, spoofing indicators, or control-channel instability.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-342: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-28388 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:O/RC:C3.92.5siemensVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/pdf/ssa-362164.pdfCVE reference, siemens
- https://cert-portal.siemens.com/productcert/pdf/ssa-344238.pdfCVE reference, siemens
- https://cert-portal.siemens.com/productcert/pdf/ssa-436469.pdfCVE reference, siemens
- https://cert-portal.siemens.com/productcert/pdf/ssa-180579.pdfCVE reference, siemens
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Predictable Exact Value from Previous Values
Predictable Exact Value from Previous Values represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.