CyberSecBulletin
CVE-2023-26299NVD status: Modified

HP PC products using AMI UEFI Firmware: Time-of-check Time-of-use (TOCTOU) Race Condition

Published Updated By the CyberSecBulletin desk

CVE-2023-26299 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in HP PC products using AMI UEFI Firmware from HP, with a CVSS 3.1 base score of 7.0 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 HP PC products using AMI UEFI Firmware versions: See HP Security Bulletin reference for affected versions.. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update 260 G4 Desktop Mini Firmware to 2.14 or a later version.
  2. Update T430 Firmware to 00.01.11 or a later version.
  3. Update T628 Firmware to 00.01.10 or a later version.
  4. Read the advisory on support.hp.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
HPHP PC products using AMI UEFI FirmwareSee HP Security Bulletin reference for affected versions.Not stated
HP260 G4 Desktop Mini Firmwarebefore 2.142.14
HPT430 Firmwarebefore 00.01.1100.01.11
HPT628 Firmwarebefore 00.01.1000.01.10
HP240 G10 Firmwarebefore f.04f.04
HP245 G6 Firmwarebefore f.35f.35
HP245 G7 Firmwarebefore f.69f.69
HP245 G8 Firmwarebefore f.25f.25
HP247 G8 Firmwarebefore f.69f.69
HP250 G10 Firmwarebefore f.05f.05
HP255 G10 Firmwarebefore f.08f.08
HP349 G7 Firmwarebefore f.28f.28
HP470 G10 Firmwarebefore f.02f.02
HP470 G9 Firmwarebefore f.05f.05
HPZhan 99 G2 Firmwarebefore f.24f.24
HPZhan 99 G4 Firmwarebefore f.08f.08
HPVr Backpack G2 Firmwarebefore f.28f.28
HP200 G3 FirmwareNot specified in the recordNot stated
HP200 G4 22 All-in-one FirmwareNot specified in the recordNot stated
HP200 Pro G4 22 All-in-one FirmwareNot specified in the recordNot stated
HP205 G4 22 All-in-one FirmwareNot specified in the recordNot stated
HP205 Pro G4 22 All-in-one FirmwareNot specified in the recordNot stated
HP280 G3 FirmwareNot specified in the recordNot stated
HP280 G4 FirmwareNot specified in the recordNot stated
HP280 G4 Microtower FirmwareNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. 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
HighSuccess depends on conditions outside the attacker's control.
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:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

A potential Time-of-Check to Time-of-Use (TOCTOU) vulnerability has been identified in certain HP PC products using AMI UEFI Firmware (system BIOS), which might allow arbitrary code execution. AMI has released updates to mitigate the potential vulnerability.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How developers prevent this class of flaw

  • The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
  • When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
  • Limit the interleaving of operations on files from multiple processes.

More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in HP PC products using AMI UEFI Firmware

All HP PC products using AMI UEFI Firmware vulnerabilities

Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities

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