CVE-2019-17190

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.

CVSS v3.0 7.8 HIGH
CVSS v2.0 7.2 HIGH

7.8^/10

CVSS v3.0 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

7.2^/10

CVSS v2.0 : HIGH

Vector : AV:L/AC:L/Au:N/C:C/I:C/A:C

Exploitability : 3.9 / Impact : 10.0

Access Vector LOCAL

Access Complexity LOW

Authentication NONE

Confidentiality Impact COMPLETE

Integrity Impact COMPLETE

Availability Impact COMPLETE

References

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

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Configurations

Configuration 1 (hide)

cpe:2.3:a:avast:secure_browser:76.0.1659.101:*:*:*:*:*:*:*

Information

Published : 2020-01-27 08:15

Updated : 2023-01-31 12:55

NVD link : CVE-2019-17190

Mitre link : CVE-2019-17190

JSON object : View

CWE

CWE-863

Incorrect Authorization

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Products Affected

avast

secure_browser

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