CyberSecBulletin
CVE-2023-4855NVD status: Deferred

SMM, SMM2, FPC: Improper Neutralization of Special Elements used in an OS Command

Published Updated By the CyberSecBulletin desk

CVE-2023-4855 is a high-severity improper neutralization of special elements used in an OS command vulnerability in SMM, SMM2, FPC from Lenovo, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected SMM, SMM2, FPC versions: various. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.13% chance of exploitation within 30 days, higher than 67% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update fan_power_controller to fhet62a-3.50 or a later version.
  2. Update system_management_module_firmware to tesm40b-1.27 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LenovoSMM, SMM2, FPCvariousNot stated
Lenovofan_power_controllerbefore fhet62a-3.50fhet62a-3.50
Lenovosystem_management_module_firmware1.24 up to, but not including, tesm40b-1.27tesm40b-1.27

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
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:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (lenovo.com).

Official description

A command injection vulnerability was identified in SMM/SMM2 and FPC that could allow an authenticated user with elevated privileges to execute unauthorized commands via IPMI.

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

The underlying weakness: Improper Neutralization of Special Elements used in an OS Command

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.

How developers prevent this class of flaw

  • If at all possible, use library calls rather than external processes to recreate the desired functionality.
  • For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)

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 SMM, SMM2, FPC

All SMM, SMM2, FPC vulnerabilities

Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities

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