Microsoft Windows up to Server 2019 Font Library memory corruption

Summaryinfo

A vulnerability classified as critical has been found in Microsoft Windows. Affected by this vulnerability is an unknown functionality of the component Font Library. Performing a manipulation results in input validation. This vulnerability is reported as CVE-2019-1145. The attack is possible to be carried out remotely. Moreover, an exploit is present. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability classified as critical has been found in Microsoft Windows (Operating System). This affects some unknown processing of the component Font Library. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. This is going to have an impact on 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 disclosed 08/13/2019 as confirmed security update guide (Website). It is possible to read the advisory at portal.msrc.microsoft.com. The public release has been coordinated in cooperation with Microsoft. This vulnerability is uniquely identified as CVE-2019-1145 since 11/26/2018. It is possible to initiate the attack remotely. No form of authentication is needed for 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 shared for download 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 (47261). The entries VDB-139891, VDB-139890, VDB-139889 and VDB-139888 are pretty similar. Be aware that VulDB is the high quality source for 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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Be aware that VulDB is the high quality source for vulnerability data.

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