Security readout for executives and security teams
Plain-English summary
This flaw lets an unauthenticated attacker run commands on a vulnerable Tianxin Internet Behavior Management System. Successful compromise could give control of the web server process and allow malicious files to be placed on the device. For exposed appliances, this is a business-critical remote takeover risk.
Executive priority
Prioritize immediately if the product is deployed, especially internet-facing. The vulnerability is unauthenticated, network reachable, critical severity, and has reported exploitation evidence. Patch or isolate affected appliances before routine remediation work.
Technical view
CVE-2021-4473 is a CWE-78 command injection issue in the Reporter component, associated with toQuery.php and objClass handling. The source bundle reports arbitrary command execution and web-root file writes, enabling remote code execution under web server privileges. The named fixed firmware is NACFirmware_4.0.0.7_20210716.180815_topsec_0_basic.bin.
Likely exposure
Organizations using Beijing Topsec Tianxin Internet Behavior Management System are the relevant population. Exposure is highest where the management or Reporter web interface is reachable from untrusted networks and firmware predates the named fixed build. The source bundle does not define a broad product matrix beyond this product.
Exploitation context
CISA KEV status is false in the provided bundle. However, the bundle reports exploitation evidence first observed by Shadowserver on 2024-06-01 UTC. Public references also include technical and exploit-tagged advisories, so defenders should treat exposed systems as high risk.
Researcher notes
Evidence is strong for impact, fixed firmware, and reported exploitation evidence, but affected version data in the bundle is sparse. Avoid assuming all Topsec products are affected. Validation should focus on product identification, firmware state, reachability, logs, and file-system indicators.
Mitigation direction
- Inventory Tianxin Internet Behavior Management System deployments and firmware versions.
- Upgrade to the named fixed firmware or follow current vendor patch guidance.
- Remove public exposure of management and Reporter interfaces where possible.
- Restrict administrative access to trusted networks or VPN paths.
- Review web roots and system integrity for unexpected PHP files.
- Monitor for web server process command execution indicators.
Validation and detection
- Confirm whether any Tianxin Internet Behavior Management System is deployed.
- Verify firmware against NACFirmware_4.0.0.7_20210716.180815_topsec_0_basic.bin or vendor guidance.
- Check external attack surface for reachable management or Reporter endpoints.
- Review logs around and after 2024-06-01 UTC for suspicious web requests.
- Inspect device web directories for unauthorized PHP files.
- Confirm compensating network controls block untrusted access.
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-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-4473 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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
2 official scoresWe 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:H/I:H/A:H3.95.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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://www.cnvd.org.cn/flaw/show/CNVD-2021-41972CVE reference, VulnCheck · government-resource
- https://www.cnvd.org.cn/patchInfo/show/280166CVE reference, VulnCheck · patch
- https://cn-sec.com/archives/4631959.htmlCVE reference, VulnCheck · technical-description, exploit
- https://avd.aliyun.com/detail?id=AVD-2021-890232CVE reference, VulnCheck · third-party-advisory
- https://www.vulncheck.com/advisories/tianxin-internet-behavior-management-system-command-injection-via-toquery-phpCVE reference, VulnCheck · third-party-advisory
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.
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.