Microsoft Windows up to Server 2019 Font Library out-of-bounds write

Summaryinfo

A vulnerability classified as critical was found in Microsoft Windows. Affected by this issue is some unknown functionality of the component Font Library. Executing a manipulation can lead to input validation. This vulnerability appears as CVE-2019-1149. The attack may be performed from remote. In addition, an exploit is available. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability classified as critical was found in Microsoft Windows (Operating System). This vulnerability affects an unknown function of the component Font Library. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A remote code execution vulnerability exists when the Windows font library improperly handles specially crafted embedded fonts. An attacker who successfully exploited the vulnerability could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. There are multiple ways an attacker could exploit the vulnerability: In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability and then convince users to view the website. An attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to click a link in an email or instant message that takes users to the attacker's website, or by opening an attachment sent through email. In a file-sharing attack scenario, an attacker could provide a specially crafted document file designed to exploit the vulnerability and then convince users to open the document file. The security update addresses the vulnerability by correcting how the Windows font library handles embedded fonts.

The weakness was presented 08/13/2019 as confirmed security update guide (Website). The advisory is shared for download at portal.msrc.microsoft.com. The public release was coordinated in cooperation with the vendor. This vulnerability was named CVE-2019-1149 since 11/26/2018. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. Technical details are unknown but a public exploit is available. The advisory points out:

A remote code execution vulnerability exists when the Windows font library improperly handles specially crafted embedded fonts. An attacker who successfully exploited the vulnerability could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

It is possible to download the exploit at packetstormsecurity.com. It is declared as proof-of-concept. As 0-day the estimated underground price was around $25k-$100k.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Exploit-DB (47264). See VDB-139891, VDB-139890, VDB-139889 and VDB-139887 for similar entries. VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 7 SP1
• 8.1
• 10
• 10 1607
• 10 1703
• 10 1709
• 10 1803
• 10 1809
• 10 1903
• RT 8.1
• Server 1803
• Server 1903
• Server 2008 R2 SP1
• Server 2008 SP2
• Server 2012
• Server 2012 R2
• Server 2016
• Server 2019

License

• commercial

Website

• Vendor: https://www.microsoft.com/
• Product: https://www.microsoft.com/en-us/windows

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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