Linux Kernel 3.19.8 x86_64 NT Flag switch_to.h Leak denial of service

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.5	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic has been found in Linux Kernel 3.19.8. This affects an unknown part in the library switch_to.h of the component x86_64 NT Flag Handler. Performing a manipulation results in denial of service (Leak). This vulnerability is known as CVE-2015-6666. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel 3.19.8 (Operating System). This affects some unknown processing in the library switch_to.h of the component x86_64 NT Flag Handler. The manipulation with an unknown input leads to a denial of service vulnerability (Leak). CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability.

The weakness was published 08/24/2015 as confirmed mailinglist post (oss-sec). It is possible to read the advisory at seclists.org. This vulnerability is uniquely identified as CVE-2015-6666 since 08/24/2015. The exploitability is told to be easy. Attacking locally is a requirement. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The reason for this vulnerability is this part of code:

#define SAVE_CONTEXT    "pushq %%rbp ; movq %%rsi,%%rbp\n\t"
#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp\t"

The vulnerability scanner Nessus provides a plugin with the ID 86078 (Fedora 21 : kernel-4.1.7-100.fc21 (2015-15933)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. A possible mitigation has been published 2 months after the disclosure of the vulnerability. The vulnerability will be addressed with the following lines of code:

#define SAVE_CONTEXT    "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"

The vulnerability is also documented in the databases at X-Force (105907) and Tenable (86078). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Operating System

Vendor

Linux

Name

Kernel

Version

3.19.8

License

open-source

Website

Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.0
VulDB Meta Temp Score: 3.5

VulDB Base Score: 4.0
VulDB Temp Score: 3.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Name: Leak
Class: Denial of service / Leak
CWE: CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Unproven
Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 86078
Nessus Name: Fedora 21 : kernel-4.1.7-100.fc21 (2015-15933)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 867773
OpenVAS Name: Fedora Update for kernel FEDORA-2015-15933
OpenVAS File: 🔍
OpenVAS Family: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Patch: git.kernel.org

Timelineinfo

08/24/2015 🔍
08/24/2015 +0 days 🔍
08/28/2015 +4 days 🔍
09/22/2015 +24 days 🔍
09/23/2015 +1 days 🔍
09/21/2018 +1094 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: seclists.org
Status: Confirmed

CVE: CVE-2015-6666 (🔍)
GCVE (CVE): GCVE-0-2015-6666
GCVE (VulDB): GCVE-100-77475
X-Force: 105907 - Linux Kernel x86_64 NT flag denial of service

Entryinfo

Created: 08/28/2015 13:15
Updated: 09/21/2018 10:05
Changes: 08/28/2015 13:15 (55), 09/21/2018 10:05 (9)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.