Security readout for executives and security teams
Plain-English summary
This Siemens issue can make affected embedded industrial products send ICMP echo replies to arbitrary network hosts when they receive crafted echo packets. It is not described as system takeover, but it can create misleading traffic and low integrity impact in operational networks.
Executive priority
Treat this as a moderate OT network integrity issue. Prioritize asset identification and Siemens advisory review, especially for networks where affected devices can receive ICMP from untrusted or broad internal segments.
Technical view
CVE-2021-31344 affects specified Siemens Capital Embedded AR Classic, PLUSCONTROL 1st Gen, and SIMOTICS CONNECT 400 versions. The flaw involves ICMP echo packets with fake IP options causing ICMP echo replies to arbitrary hosts. CVSS v4.0 is 6.9 with network, unauthenticated, low-complexity access and low integrity impact.
Likely exposure
Exposure is most likely in industrial or embedded environments running the listed Siemens products on networks where ICMP traffic can reach the device. Internet exposure is not stated in the sources and should not be assumed.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. The attack surface is network-reachable ICMP handling and does not require authentication or user interaction, according to the CVSS vector.
Researcher notes
Evidence is limited to the CVE record and Siemens advisory references in the source bundle. CWE-843 is listed, but the functional description centers on malformed ICMP/IP option handling causing replies to arbitrary hosts. No exploit details or active exploitation evidence are provided.
Mitigation direction
- Inventory the listed Siemens products and record exact firmware or software versions.
- Check Siemens ProductCERT advisories for product-specific fixes and workarounds.
- Update Capital Embedded AR Classic R20-11 to V2303 or later where applicable.
- Update SIMOTICS CONNECT 400 to a non-affected Siemens-supported version where applicable.
- For products listed as all versions affected, follow Siemens guidance before assuming a patch exists.
Validation and detection
- Confirm whether any affected Siemens product is deployed in OT or embedded networks.
- Verify product versions against the affected version ranges in the CVE record.
- Review network paths where ICMP can reach these devices.
- Check monitoring for unusual ICMP echo reply patterns involving affected assets.
- Document advisory status, compensating controls, and planned remediation owners.
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-843: 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-2021-31344 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
- 6.9 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
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.
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
6.9MediumVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/pdf/ssa-114589.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-044112.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-620288.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-845392.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-223353.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/html/ssa-114589.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-044112.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-620288.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-845392.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-223353.htmlCVE reference
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.
Access of Resource Using Incompatible Type ('Type Confusion')
Access of Resource Using Incompatible Type ('Type Confusion') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.