Linux Kernel nfc_llcp_build_tlv Function Denial of Service Vulnerability [CVE-2019-12818]

CVE Number – CVE-2019-12818

A vulnerability in the Linux Kernel could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on a targeted system.

The vulnerability is due to a NULL pointer dereference condition that could occur if the nfc_llcp_build_tlv function, as defined in the net/nfc/llcp_commands.c source code file of the affected software, returns NULL. This condition could also affect the nfc_llcp_build_gb function in the net/nfc/llcp_core.c source code file. An attacker could exploit the vulnerability by sending a request that submits malicious input to the targeted system. A successful exploit could result in a DoS condition.Kernel.org has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, the attacker must have short range wireless connectivity to the targeted system to send a request that submits malicious input to the system. This access requirement may reduce the likelihood of a successful exploit.

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

• Kernel.org has released a changelog at the following link: Kernel ChangeLog-4.20.15

Fixed Software

• Kernel.org has released a git commit at the following link: net: nfc: Fix NULL dereference on nfc_llcp_build_tlv fails