dhcpcd Authentication Hash Comparison Latency Vulnerability [CVE-2019-11578]

CVE Number – CVE-2019-11578

A vulnerability in the authentication implementation of dhcpcd could allow an unauthenticated, remote attacker to access sensitive information on a targeted system.

The vulnerability exists because the affected software, as defined in the src/auth.c source code file, does not properly perform cryptographic hash comparisons. An attacker could exploit this vulnerability by sending requests that submit malicious input to the affected system. A successful exploit could allow the attacker to perform latency attacks and access sensitive information, which could be used to conduct additional attacks..

The vendor has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, the attacker must send malicious requests to the targeted system, this could make exploitation more difficult in environments that restrict network access from untrusted sources.

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 run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.
  
  Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
  
  Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
  
  Administrators are advised to monitor affected systems.

Vendor Announcements

• The vendor has published a release announcement at the following link: dhcpcd-7.2.1 has been released

Fixed Software

• The vendor has published source code and software updates at the following links: auth: Use consttime_memequal(3) to compare hashes and dhcpcd – a DHCP client