CVE-2021-0258 : Security Advisory and Response
Learn about CVE-2021-0258, a vulnerability in Juniper Networks Junos OS enabling a Denial of Service (DoS) attack through transit TCPv6 packets on the management interface. Mitigation steps and software updates provided.
A vulnerability in the forwarding of transit TCPv6 packets on the Ethernet management interface of Juniper Networks Junos OS can trigger a kernel panic, resulting in a Denial of Service (DoS) attack.
Understanding CVE-2021-0258
This CVE highlights a security flaw in Juniper Networks Junos OS that allows an attacker to cause a Denial of Service through transit TCPv6 packets.
What is CVE-2021-0258?
The vulnerability in Junos OS enables an attacker to induce a kernel panic by forwarding transit TCPv6 packets on the Ethernet management interface, leading to a DoS attack.
The Impact of CVE-2021-0258
On affected systems, routing TCPv6 packets through the management interface can result in a sustained DoS condition. This vulnerability affects Junos OS versions 17.2 to 19.4.
Technical Details of CVE-2021-0258
This section delves into the specifics of the vulnerability, including the description, affected systems, and exploitation mechanism.
Vulnerability Description
The flaw allows for the triggering of a kernel panic upon receipt of specific TCPv6 packets via the management interface, potentially causing a sustained DoS condition.
Affected Systems and Versions
Systems running Junos OS versions 17.2 to 19.4 are vulnerable to this issue, especially those with the concurrent network stack feature enabled.
Exploitation Mechanism
An attacker can exploit this vulnerability by sending transit TCPv6 packets through the Ethernet management interface, leading to a kernel panic and subsequent DoS.
Mitigation and Prevention
To mitigate the risks associated with CVE-2021-0258, certain immediate steps need to be taken, and long-term security practices should be implemented.
Immediate Steps to Take
Disable TCP Parallelization to prevent the exploitation of the vulnerability through the management interface.
Long-Term Security Practices
Regularly apply software updates provided by Juniper Networks to safeguard against known vulnerabilities and maintain the security of Junos OS.
Patching and Updates
Juniper Networks has released updated software versions from 17.2R3-S4 to 20.1R1, which address and resolve the CVE-2021-0258 vulnerability.