Linux Kernel up to 4.14.90/4.19.12 KVM Hypervisor nested_get_vmcs12_pages use after free

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.
7.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 4.14.90/4.19.12. It has been classified as critical. This impacts the function nested_get_vmcs12_pages of the component KVM Hypervisor. This manipulation causes use after free. This vulnerability is registered as CVE-2018-16882. The attack needs to be launched locally. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 4.14.90/4.19.12 (Operating System). Affected by this vulnerability is the function nested_get_vmcs12_pages of the component KVM Hypervisor. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A use-after-free issue was found in the way the Linux kernel's KVM hypervisor processed posted interrupts when nested(=1) virtualization is enabled. In nested_get_vmcs12_pages(), in case of an error while processing posted interrupt address, it unmaps the 'pi_desc_page' without resetting 'pi_desc' descriptor address, which is later used in pi_test_and_clear_on(). A guest user/process could use this flaw to crash the host kernel resulting in DoS or potentially gain privileged access to a system. Kernel versions before 4.14.91 and before 4.19.13 are vulnerable.

The bug was discovered 12/18/2018. The weakness was published 01/03/2019 as confirmed bug report (Bugzilla). The advisory is shared at bugzilla.redhat.com. This vulnerability is known as CVE-2018-16882 since 09/11/2018. The exploitation appears to be easy. An attack has to be approached locally. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 16 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 121470 (Ubuntu 18.04 LTS : linux-hwe vulnerabilities (USN-3872-1)), 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 197355 (Ubuntu Security Notification for Linux-hwe Vulnerabilities (USN-3872-1)).

Upgrading to version 4.14.91, 4.14.90 or 4.19.13 eliminates this vulnerability. A possible mitigation has been published 4 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (121470) and SecurityFocus (BID 106254†). Similar entries are available at VDB-122170 and VDB-130426. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.1
VulDB Meta Temp Score: 7.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 8.8
NVD Vector: 🔍

CNA Base Score: 6.1
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

NVD Base Score: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 121470
Nessus Name: Ubuntu 18.04 LTS : linux-hwe vulnerabilities (USN-3872-1)
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: 🔍

Upgrade: Kernel 4.14.91/4.14.90/4.19.13

Timelineinfo

09/11/2018 🔍
12/18/2018 +98 days 🔍
12/18/2018 +0 days 🔍
01/03/2019 +16 days 🔍
01/03/2019 +0 days 🔍
01/04/2019 +1 days 🔍
01/29/2019 +25 days 🔍
01/30/2019 +1 days 🔍
06/23/2023 +1605 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: USN-3872-1
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2018-16882 (🔍)
GCVE (CVE): GCVE-0-2018-16882
GCVE (VulDB): GCVE-100-128665
SecurityFocus: 106254 - Linux Kernel CVE-2018-16882 Local Denial of Service Vulnerability

See also: 🔍

Entryinfo

Created: 01/04/2019 12:17
Updated: 06/23/2023 07:26
Changes: 01/04/2019 12:17 (75), 04/25/2020 21:21 (10), 06/23/2023 07:15 (4), 06/23/2023 07:20 (13), 06/23/2023 07:26 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to know what is going to be exploited?

We predict KEV entries!