CVE-2021-21538
About
Dell EMC iDRAC9 versions 4.40.00.00 and later, but prior to 4.40.10.00, contain an improper authentication vulnerability. A remote unauthenticated attacker could potentially exploit this vulnerability to gain access to the virtual console.
Rainforest analyst review
An improper-authentication flaw in Dell EMC iDRAC9 firmware lets a remote, unauthenticated attacker potentially reach the virtual console, with the vector noting some user interaction. Console access to an iDRAC is roughly equivalent to standing at the server's keyboard, so this is authentication failing on a very sensitive surface.
iDRAC is out-of-band management, the interface that controls the server beneath the operating system, which is why unauthenticated access to its virtual console rates so high. The mitigating detail is the narrow affected firmware band, so the exposed population is bounded by version even before you consider network placement.
Our overriding angle is exposure: an iDRAC should never be reachable from the internet or general user networks, full stop. We hunt for any management interface that's improperly exposed, push it behind a segmented management network, and inventory firmware against the affected range. Network isolation is the control that neutralizes this regardless of the auth bug.
References
Related CVEs
Frequently asked questions
What is CVE-2021-21538?
Dell EMC iDRAC9 versions 4.40.00.00 and later, but prior to 4.40.10.00, contain an improper authentication vulnerability. A remote unauthenticated attacker could potentially exploit this vulnerability to gain access to the virtual console.
How severe is CVE-2021-21538?
CVE-2021-21538 carries a CVSS 3.1 base score of 9.6, rated critical. On the Rainforest Risk Index — which weighs the severity alongside how easy the flaw is to reach and how broad its impact is — it scores 94 out of 100, in the critical band.
How is CVE-2021-21538 exploited?
According to the CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L): attack vector Network, attack complexity Low, privileges required None, user interaction Required. Impact on confidentiality High, integrity High and availability Low.
Which products are affected by CVE-2021-21538?
Public advisories list the following as affected: idrac9 firmware. Check the references on this page for the exact versions each vendor confirms.
How do I fix CVE-2021-21538?
Apply the fix the vendor published — the references on this page link to the primary advisories and patches. When patching can't happen right away, reduce the exposure of the affected component and watch it for exploitation attempts. Rainforest customers see this vulnerability correlated to their own assets and prioritized by real exposure, not by score alone.
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