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4.5	$0-$5k	0.00

A vulnerability has been found in Linux Kernel 3.17.3 on ARM64 (Operating System) and classified as problematic. This vulnerability affects an unknown code block. The manipulation as part of a n*PAGE_SIZE+1 leads to a code vulnerability. The CWE definition for the vulnerability is CWE-17. As an impact it is known to affect availability. CVE summarizes:

The __clear_user function in arch/arm64/lib/clear_user.S in the Linux kernel before 3.17.4 on the ARM64 platform allows local users to cause a denial of service (system crash) by reading one byte beyond a /dev/zero page boundary.

The weakness was released 11/13/2014 by Miloš Prchlík as confirmed posting (Mailing List). The advisory is available at lkml.org. This vulnerability was named CVE-2014-7843 since 10/03/2014. The exploitation appears to be difficult. Local access is required to approach this attack. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The advisory points out:

ARM64 currently doesn't fix up faults on the single-byte (strb) case of __clear_user... which means that we can cause a nasty kernel panic as an ordinary user with any multiple PAGE_SIZE+1 read from /dev/zero. i.e.: dd if=/dev/zero of=foo ibs=1 count=1 (or ibs=65537, etc.)

The vulnerability scanner Nessus provides a plugin with the ID 79319 (Fedora 21 : kernel-3.17.3-300.fc21 (2014-15159)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 123449 (Fedora Security Update for kernel (FEDORA-2015-3594)). The advisory illustrates:

This is a pretty obscure bug in the general case since we'll only __do_kernel_fault (since there's no extable entry for pc) if the mmap_sem is contended. However, with CONFIG_DEBUG_VM enabled, we'll always fault.

The vulnerability is also documented in the databases at X-Force (98660) and Tenable (79319). Additional details are provided at bugzilla.redhat.com. Entries connected to this vulnerability are available at 68204, 68205 and 68209.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 3.17.3

License

• open-source

CPE 2.3info

• 🔍

CPE 2.2info

• 🔍

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 4.5

VulDB Base Score: 5.1
VulDB Temp Score: 4.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Code
CWE: CWE-17
ATT&CK: Unknown

Local: Yes
Remote: No

Availability: 🔍
Status: Unproven

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Nessus ID: 79319
Nessus Name: Fedora 21 : kernel-3.17.3-300.fc21 (2014-15159)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

OpenVAS ID: 867487
OpenVAS Name: Fedora Update for kernel FEDORA-2014-17283
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Patch: 97fc15436b36ee3956efad83e22a557991f7d19d

Timelineinfo

10/03/2014 🔍
11/13/2014 +41 days 🔍
11/13/2014 +0 days 🔍
11/13/2014 +0 days 🔍
11/14/2014 +1 days 🔍
11/29/2014 +15 days 🔍
12/01/2014 +2 days 🔍
01/14/2015 +44 days 🔍
02/24/2022 +2598 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: 97fc15436b36ee3956efad83e22a557991f7d19d
Researcher: Miloš Prchlík
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2014-7843 (🔍)
X-Force: 98660 - Linux Kernel dev zero denial of service, Medium Risk
Vulnerability Center: 47333 - Linux Kernel before 3.17.4 Local DoS via Read Beyond Page Boundary, Medium
SecurityFocus: 71082 - Linux Kernel CVE-2014-7843 Local Denial of Service Vulnerability
Secunia: 62305 - Ubuntu update for kernel, Moderately Critical

Misc.: 🔍
See also: 🔍

Entryinfo

Created: 11/14/2014 12:24
Updated: 02/24/2022 20:30
Changes: 11/14/2014 12:24 (81), 06/13/2017 08:36 (3), 02/24/2022 20:22 (5), 02/24/2022 20:30 (1)
Complete: 🔍

Discussion

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