Xen up to 4.14.x TLB Entry memory corruption

entryeditHistoryDiffjsonxmlCTI

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.
6.4	$5k-$25k	0.00

A vulnerability, which was classified as critical, has been found in Xen up to 4.14.x (Virtualization Software). This issue affects some unknown processing of the component TLB Entry Handler. The manipulation with an unknown input leads to a memory corruption vulnerability. Using CWE to declare the problem leads to CWE-119. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

An issue was discovered in Xen through 4.14.x allowing x86 PV guest OS users to gain guest OS privileges by modifying kernel memory contents, because invalidation of TLB entries is mishandled during use of an INVLPG-like attack technique.

The weakness was published 10/23/2020. The advisory is shared at xenbits.xen.org. The identification of this vulnerability is CVE-2020-27674 since 10/22/2020. Access to the local network is required for this attack to succeed. Required for exploitation is a simple authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 11/26/2020).

Applying a patch is able to eliminate this problem.

Productinfoedit

Type

Virtualization Software

Name

CPE 2.3infoedit

CPE 2.2infoedit

CVSSv3infoedit

VulDB Meta Base Score: 6.7
VulDB Meta Temp Score: 6.4

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.3
NVD Vector: 🔒

CVSSv2infoedit

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VulDB Base Score: 🔒
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VulDB Reliability: 🔍

NVD Base Score: 🔒

Exploitinginfoedit

Class: Memory corruption
CWE: CWE-119
ATT&CK: Unknown

Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfoedit

Threat: 🔍
Adversaries: 🔍
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Predictions: 🔍
Remediation: 🔍

Countermeasuresinfoedit

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfoedit

10/22/2020 CVE assigned
10/23/2020 +1 days Advisory disclosed
10/23/2020 +0 days VulDB entry created
11/26/2020 +34 days VulDB last update

Sourcesinfoedit

Advisory: xenbits.xen.org
Status: Confirmed

CVE: CVE-2020-27674 (🔒)

Entryinfoedit