CVE Number – CVE-2018-15688
A vulnerability in the DHCPv6 client of systemd could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a denial of service (DoS) condition on a targeted system.
The vulnerability exists because the systemd-networkd system daemon improperly handles the size of the temporary buffer that is used to construct DHCPv6 packets to be sent to DCHPv6 servers. An attacker could exploit this vulnerability by advertising an attacker-controlled DHCPv6 server and sending DHCPv6 options to be handled by an affected DCHPv6 client system. A successful exploit could cause an integer underflow condition that could lead to a heap-based buffer overflow condition that the attacker could use to execute arbitrary code or cause a DoS condition.
The vendor has confirmed the vulnerability and released software updates.
To exploit this vulnerability, the attacker must be in control of a DCHPv6 server and on the same internal, trusted network as the targeted DHCPv6 client system. These requirements may reduce the likelihood of a successful exploit.
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.
The vendor has released a pull request at the following link: Pull #10518
The vendor has released software updates at the following link: dhcp6 packet size calculation fixes #10518
Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.