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

Summaryinfo

A vulnerability, which was classified as critical, has been found in Microsoft Windows. This affects an unknown part of the component Font Library. The manipulation leads to input validation. This vulnerability is traded as CVE-2019-1150. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Microsoft Windows (Operating System). This issue affects an unknown functionality of the component Font Library. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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 shared 08/13/2019 as confirmed security update guide (Website). The advisory is shared at portal.msrc.microsoft.com. The vendor cooperated in the coordination of the public release. The identification of this vulnerability is CVE-2019-1150 since 11/26/2018. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. 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.

The exploit is available at packetstormsecurity.com. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $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 (47265). The entries VDB-139893, VDB-139891, VDB-139890 and VDB-139888 are related to this item. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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