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WiX Burn-based bundles are vulnerable to binary hijack when run as SYSTEM

High
robmen published GHSA-rf39-3f98-xr7r Mar 23, 2024

Package

nuget WixToolset.Sdk (NuGet)

Affected versions

< 4.0.5

Patched versions

4.0.5
nuget wix (NuGet)
< 3.14.1
>= 4, < 4.0.5
3.14.1
4.0.5

Description

Summary

Burn uses an unprotected C:\Windows\Temp directory to copy binaries and run them from there. This directory is not entirely protected against low privilege users.

Details

When a bundle runs as SYSTEM user, Burn uses GetTempPathW which points to an insecure directory C:\Windows\Temp to drop and load multiple binaries. Standard users can hijack the binary before it's loaded in the application resulting in elevation of privileges.

icacls c:\windows\temp

BUILTIN\Users:(CI)(S,WD,AD,X)
BUILTIN\Administrators:(F)
BUILTIN\Administrators:(OI)(CI)(IO)(F)
NT AUTHORITY\SYSTEM:(F)
NT AUTHORITY\SYSTEM:(OI)(CI)(IO)(F)
CREATOR OWNER:(OI)(CI)(IO)(F)

Built in users(non-administrators) have special permissions to this folder and can create files and write to this directory. While they do not have explicit read permissions, there is a way they can monitor the changes to this directory using ReadDirectoryChangesW API and thus figure out randomized folder names created inside this directory as wel
 

PoC

PoC works against the against visual studio enterprise with update 3 installer

Reproduction steps

As a standard user, run the poc.
Mount the iso and run visual studio installer as local system account.
The PoC should hijack the the binaries dropped by vs installer and a child process "notepad.exe" will be running.

Impact

This is an Elevation of Privilege Vulnerability where a low privileged user can hijack binaries in an unprotected path C:\Windows\Temp to elevate to the SYSTEM user privileges.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CVE ID

CVE-2024-29187

Weaknesses

No CWEs

Credits