GNOME libcroco cr_parser_parse_selector_core Function Denial of Service Vulnerability [CVE-2017-8871]

CVE Number – CVE-2017-8871

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

The vulnerability exists in the cr_parser_parse_selector_core function, as defined in the src/cr-parser.c source code file of the affected software. The vulnerability manifests as an infinite loop error condition leading to CPU exhaustion. An attacker could exploit this vulnerability by persuading a user to access a file that submits malicious input to the system. A successful exploit could allow the attacker to cause a DoS condition on the system.Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available.The GNOME Project has confirmed the vulnerability and released a proposed patch.

Analysis

• To exploit this vulnerability, the attacker may use misleading language or instructions to persuade a user to access a file that submits malicious input to the affected software.

Safeguards

• Administrators are advised to apply the appropriate updates.
  
  Administrators are advised to allow only trusted users to have network access.
  
  Administrators are advised to use an unprivileged account when browsing the Internet.
  
  Administrators are advised to monitor critical systems.
  
  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.

Vendor Announcements

• The GNOME Project has confirmed the vulnerability in a bug report at the following link: Bug 782649 – (CVE-2017-8871) libcroco 0.6.12 DoS 2

Fixed Software

• The GNOME Project has published a proposed patch with the bug report; however, at the time this alert was first published, software updates had not been released.