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CVE-2019-17190 Detail

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.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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 Third Party Advisory  VDB Entry 
http://packetstormsecurity.com/files/156844/Avast-Secure-Browser-76.0.1659.101-Local-Privilege-Escalation.html Third Party Advisory  VDB Entry 
http://seclists.org/fulldisclosure/2020/Mar/25 Mailing List  Third Party Advisory 
http://seclists.org/fulldisclosure/2020/Mar/25 Mailing List  Third Party Advisory 
https://www.avast.com/bug-bounty-credits/en/a-tribute-to-our-security-research-community Vendor Advisory 
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-863 Incorrect Authorization cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

8 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2019-17190
NVD Published Date:
01/27/2020
NVD Last Modified:
11/20/2024
Source:
MITRE