Security readout for executives and security teams
Plain-English summary
CVE-2021-28208 lets an administrator-level remote user abuse an ASUS BMC web management function to read system files through path traversal. The attacker already needs administrator permission, which limits likelihood, but BMCs control sensitive server-management planes, so exposure matters.
Executive priority
Treat this as a targeted management-plane confidentiality risk. It is not known to be actively exploited and requires admin access, but affected BMCs should be reviewed because compromise can expose sensitive system files on infrastructure management devices.
Technical view
The Get video file function in ASUS BMC firmware fails to filter a specific parameter, allowing CWE-22 path traversal. The CVSS 3.1 vector is 4.9: network-accessible, low complexity, high privileges required, no user interaction, high confidentiality impact, no integrity or availability impact.
Likely exposure
Exposure is likely limited to organizations running the listed ASUS BMC firmware versions on ASMB9-iKVM and affected RS, ESC, E700, WS, Z11, and KNPA systems. Risk rises if BMC web management is reachable beyond a tightly controlled management network.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. Exploitation requires administrator permission on the BMC web interface, so stolen, shared, or overprivileged BMC credentials are the main concern.
Researcher notes
Evidence is strong for vulnerability type, affected versions, CVSS, and privilege requirement. The source bundle does not provide fixed versions, exploit observations, or detailed mitigation steps, so remediation should be verified against ASUS or TWCERT advisories.
Mitigation direction
- Inventory ASUS BMC devices and compare firmware versions against the affected list.
- Check ASUS and TWCERT guidance for corrected firmware or vendor-approved remediation.
- Restrict BMC web management to trusted management networks or VPN access.
- Enforce unique administrator credentials and remove unnecessary BMC admin accounts.
- Monitor BMC authentication and file-access activity for unexpected administrator behavior.
Validation and detection
- Identify ASUS BMC model and firmware version on each managed server.
- Confirm whether each device matches an affected product and version.
- Verify BMC web management is not internet-exposed.
- Review administrative account lists for stale, shared, or excessive privileges.
- Check BMC logs for unusual administrator sessions or file 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-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-28208 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
- 4.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A: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:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N1.23.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.9MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.asus.com/content/ASUS-Product-Security-Advisory/CVE reference · x_refsource_MISC
- https://www.asus.com/tw/support/callus/CVE reference · x_refsource_MISC
- https://www.twcert.org.tw/tw/cp-132-4578-e5d74-1.htmlCVE reference · 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.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.