Memcached lru Commands NULL Pointer Dereference Vulnerablity [CVE-2019-11596]

CVE Number – CVE-2019-11596

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

The vulnerability exists because the lru mode and lru temp_ttl commands, as implemented in thememcached.c source code file, do not properly perform memory operations, which could result in a NULL pointer dereference memory operation error. 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 cause a segmentation fault in the affected software, resulting in a DoS condition. 

Memcached has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, the attacker must send requests to the targeted system, makinig 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

• Memcached has published a release note at the following link: Memcached 1.5.14 Release Notes

Fixed Software

• Memcached has published source code and software updates at the following links: fix segfault in “lru” command and 1.5.14