CVE-2019-0841

An elevation of privilege vulnerability exists when Windows AppX Deployment Service (AppXSVC) improperly handles hard links, aka Windows Elevation of Privilege Vulnerability. This CVE ID is unique from CVE-2019-0730, CVE-2019-0731, CVE-2019-0796, CVE-2019-0805, CVE-2019-0836.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• http://packetstormsecurity.com/files/152463/Microsoft-Windows-AppX-Deployment-Service-Privilege-Escalation.html
• http://packetstormsecurity.com/files/153009/Internet-Explorer-JavaScript-Privilege-Escalation.html
• http://packetstormsecurity.com/files/153114/Microsoft-Windows-AppX-Deployment-Service-Local-Privilege-Escalation.html
• http://packetstormsecurity.com/files/153215/Microsoft-Windows-AppX-Deployment-Service-Local-Privilege-Escalation.html
• http://packetstormsecurity.com/files/153642/AppXSvc-Hard-Link-Privilege-Escalation.html
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0841
• https://www.exploit-db.com/exploits/46683/
• https://www.zerodayinitiative.com/advisories/ZDI-19-360/