HarfBuzz Invalid Read Denial of Service Vulnerability [CVE-2015-9274 ]

CVE Number – CVE-2015-9274

A vulnerability in HarfBuzz could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.

The vulnerability is due to improper handling of Glyph Positioning (GPOS) and Glyph Substitution (GSUB) tables related to the hb-ot-layout-gpos-table.hh, hb-ot-layout-gsub-table.hh, and hb-ot-layout-gsubgpos-private.hh source code files of the affected software. An attacker could exploit this vulnerability by persuading a user to access a file that submits malicious input to the targeted system. An exploit could cause an invalid read condition that causes the affected application to crash, resulting in a DoS condition. 

HarfBuzz has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, an attacker may use misleading language and instructions to persuade a user to open a file that submits malicious input to the targeted system.

Safeguards

• Administrators are advised to apply the appropriate updates.
  
  Administrators are advised to allow only trusted users to have network access.
  
  Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email messages are safe, they are advised not to open them.
  
  Users are advised not to visit websites or follow links that have suspicious characteristics or cannot be verified as safe.
  
  Administrators are advised to use an unprivileged account when browsing the Internet.
  
  Administrators are advised to monitor critical systems.

Vendor Announcements

• HarfBuzz has released a git commit at the following link: commit c917965b9e6fe2b21ed6c51559673288fa3af4b7

Fixed Software

• HarfBuzz has released software updates at the following link: HarfBuzz 1.0.4