// For flags

CVE-2015-7837

kernel: securelevel disabled after kexec

Severity Score

5.5
*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

The Linux kernel, as used in Red Hat Enterprise Linux 7, kernel-rt, and Enterprise MRG 2 and when booted with UEFI Secure Boot enabled, allows local users to bypass intended securelevel/secureboot restrictions by leveraging improper handling of secure_boot flag across kexec reboot.

El kernel de Linux, tal y como se emplea en Red Hat Enterprise Linux 7, kernel-rt y Enterprise MRG 2 y cuando se emplea con UEFI Secure Boot habilitado, permite que usuarios locales omitan las restricciones securelevel/secureboot previstas aprovechando la gestiĆ³n incorrecta de la marca secure_boot cuando se reinicia kexec.

A flaw was found in the way the Linux kernel handled the securelevel functionality after performing a kexec operation. A local attacker could use this flaw to bypass the security mechanism of the securelevel/secureboot combination.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
Attack Vector
Local
Attack Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2015-10-15 CVE Reserved
  • 2015-11-20 CVE Published
  • 2023-03-08 EPSS Updated
  • 2024-08-06 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-254: 7PK - Security Features
  • CWE-456: Missing Initialization of a Variable
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Redhat
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Enterprise Linux
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7.0
Search vendor "Redhat" for product "Enterprise Linux" and version "7.0"
-
Affected
Redhat
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Enterprise Linux
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7.2
Search vendor "Redhat" for product "Enterprise Linux" and version "7.2"
-
Affected
Redhat
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Enterprise Linux
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7.3
Search vendor "Redhat" for product "Enterprise Linux" and version "7.3"
-
Affected
Redhat
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Enterprise Linux Desktop
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7.0
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-
Affected
Redhat
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Enterprise Linux Server Aus
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7.3
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-
Affected
Redhat
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Enterprise Linux Server Aus
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7.4
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-
Affected
Redhat
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Enterprise Linux Workstation
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7.0
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-
Affected
Redhat
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Enterprise Mrg
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2.0
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-
Affected
Redhat
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Kernel-rt
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7.0
Search vendor "Redhat" for product "Kernel-rt" and version "7.0"
-
Affected