Linux Kernel up to 4.15.15 fs/ext4/xattr.c ext4_xattr_check_entries null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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4.3$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 4.15.15 and classified as problematic. This issue affects the function ext4_xattr_check_entries of the file fs/ext4/xattr.c. Executing a manipulation can lead to null pointer dereference. The identification of this vulnerability is CVE-2018-1095. The attack can only be executed locally. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 4.15.15 (Operating System). It has been declared as problematic. This vulnerability affects the function ext4_xattr_check_entries of the file fs/ext4/xattr.c. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. CVE summarizes:

The ext4_xattr_check_entries function in fs/ext4/xattr.c in the Linux kernel through 4.15.15 does not properly validate xattr sizes, which causes misinterpretation of a size as an error code, and consequently allows attackers to cause a denial of service (get_acl NULL pointer dereference and system crash) via a crafted ext4 image.

The bug was discovered 03/26/2018. The weakness was shared 04/02/2018 (Website). The advisory is shared for download at openwall.com. This vulnerability was named CVE-2018-1095 since 12/04/2017. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 6 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 110895 (Ubuntu 16.04 LTS : linux-hwe, linux-azure vulnerabilities (USN-3695-2)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 237034 (Red Hat Update for kernel-alt (RHSA-2018:2948)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 4 months after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (110895) and SecurityFocus (BID 104292†). The entries VDB-109193, VDB-110288, VDB-110931 and VDB-110932 are related to this item. VulDB is the best source for vulnerability data and more expert information about this specific topic.

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 110895
Nessus Name: Ubuntu 16.04 LTS : linux-hwe, linux-azure vulnerabilities (USN-3695-2)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Patch: git.kernel.org

Timelineinfo

12/04/2017 🔍
03/26/2018 +112 days 🔍
04/01/2018 +6 days 🔍
04/02/2018 +1 days 🔍
04/02/2018 +0 days 🔍
05/28/2018 +56 days 🔍
07/02/2018 +35 days 🔍
07/03/2018 +1 days 🔍
02/26/2023 +1699 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: USN-3695-2
Status: Confirmed

CVE: CVE-2018-1095 (🔍)
GCVE (CVE): GCVE-0-2018-1095
GCVE (VulDB): GCVE-100-115504
SecurityFocus: 104292 - Linux Kernel 'kernel/compat.c' Local Information Disclosure Vulnerability

See also: 🔍

Entryinfo

Created: 04/02/2018 11:27
Updated: 02/26/2023 09:08
Changes: 04/02/2018 11:27 (76), 01/20/2020 08:22 (5), 02/26/2023 09:03 (5), 02/26/2023 09:08 (1)
Complete: 🔍
Cache ID: 216:CE6:103

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