CVE-2019-17190 Detail

Current Description

A Local Privilege Escalation issue was discovered in Avast Secure Browser 76.0.1659.101. The vulnerability is due to an insecure ACL set by the AvastBrowserUpdate.exe (which is running as NT AUTHORITY\SYSTEM) when AvastSecureBrowser.exe checks for new updates. When the update check is triggered, the elevated process cleans the ACL of the Update.ini file in %PROGRAMDATA%\Avast Software\Browser\Update\ and sets all privileges to group Everyone. Because any low-privileged user can create, delete, or modify the Update.ini file stored in this location, an attacker with low privileges can create a hard link named Update.ini in this folder, and make it point to a file writable by NT AUTHORITY\SYSTEM. Once AvastBrowserUpdate.exe is triggered by the update check functionality, the DACL is set to a misconfigured value on the crafted Update.ini and, consequently, to the target file that was previously not writable by the low-privileged attacker.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.8 HIGH
Vector:  CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://packetstormsecurity.com/files/156844/Avast-Secure-Browser-76.0.1659.101-Local-Privilege-Escalation.html
http://seclists.org/fulldisclosure/2020/Mar/25
https://www.avast.com/bug-bounty-credits/en/a-tribute-to-our-security-research-community Vendor Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-269 Improper Privilege Management cwe source acceptance level NIST  

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Change History

4 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2019-17190
NVD Published Date:
01/27/2020
NVD Last Modified:
03/20/2020
Source:
MITRE