Security readout for executives and security teams
Plain-English summary
This Siemens industrial control vulnerability can force affected PLC, TDC, and SINUMERIK devices into defect mode through unauthenticated network traffic. Recovery requires a restart, so the business impact is operational downtime rather than data theft.
Executive priority
Treat as high priority for industrial environments where affected devices support production, safety-adjacent operations, or critical availability. Prioritize exposed or remotely reachable assets first.
Technical view
CVE-2019-18336 affects listed Siemens SIMATIC S7-300, related ET200/SIPLUS variants, TDC CP51M1, TDC CPU555, and SINUMERIK 840D sl versions. Crafted packets to TCP port 102 can trigger a denial of service with high availability impact. CVSS 3.1 is 7.5.
Likely exposure
Exposure is most likely where affected Siemens industrial devices have TCP/102 reachable from plant networks, engineering networks, remote access paths, or poorly segmented IT/OT connections.
Exploitation context
The bundle states no authentication or user interaction is required. Siemens reported no known public exploitation at advisory publication, and KEV status is false in the provided data.
Researcher notes
The evidence supports unauthenticated network denial of service against TCP/102 only. It does not support confidentiality, integrity, code execution, or active exploitation claims. The SINUMERIK version entries need vendor-advisory confirmation by product branch.
Mitigation direction
- Upgrade affected Siemens products to vendor-fixed versions where available.
- Restrict TCP/102 access to trusted engineering and control-system hosts.
- Segment affected OT assets from corporate and internet-reachable networks.
- Review Siemens SSA-508982 for product-specific firmware and compensating guidance.
- Plan controlled restarts because recovery from defect mode requires reboot.
Validation and detection
- Inventory Siemens models and firmware versions against the affected-version list.
- Confirm whether TCP/102 is reachable from non-essential networks.
- Check firewall, VPN, and remote-access paths into OT segments.
- Review outage logs for unexplained defect-mode events requiring restart.
- Verify remediation status against Siemens advisory SSA-508982.
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
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ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2019-18336 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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:N/A:H3.93.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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-508982.pdfCVE reference, siemens · x_refsource_MISC
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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.