Dell dbutil Driver Insufficient Access Control
CVE-2021-21551 is a high-severity exposed IOCTL with insufficient access control vulnerability in dbutil from Dell, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected dbutil versions: 2.3. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on March 31, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of dbutil you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on dell.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA (emc.com) |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 2.0 | 4.6 | Medium | NVD |
Official description
Dell dbutil_2_3.sys driver contains an insufficient access control vulnerability which may lead to escalation of privileges, denial of service, or information disclosure. Local authenticated user access is required.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Exposed IOCTL with Insufficient Access Control
The product implements an IOCTL with functionality that should be restricted, but it does not properly enforce access control for the IOCTL.
How developers prevent this class of flaw
- In Windows environments, use proper access control for the associated device or device namespace. See References.
More Exposed IOCTL with Insufficient Access Control vulnerabilities (CWE-782)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21551US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/162604/Dell-DBUtil_2_3.sys-IOCTL-Memory-Read-Write.htmlExploit, Third Party Advisory, VDB Entry
- packetstormsecurity.com/files/162739/DELL-dbutil_2_3.sys-2.3-Arbitrary-Write-Privilege-Escalation.htmlExploit, Third Party Advisory, VDB Entry
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