CVE-2021-0263 : Security Advisory and Response
Learn about CVE-2021-0263, a Data Processing vulnerability in Juniper Networks Junos OS on PTX Series routers leading to a Denial of Service condition. Find out the impacted systems, mitigation steps, and solution.
A Data Processing vulnerability in the Multi-Service process (multi-svcs) on the FPC of Juniper Networks Junos OS on the PTX Series routers may lead to a Denial of Service (DoS) condition. The issue arises due to heavy route churn when J-Flow sampling is enabled, causing the Multi-Service Process to become unresponsive, affecting traffic forwarding.
Understanding CVE-2021-0263
This CVE details a vulnerability in Junos OS on PTX Series routers that can be exploited to cause a Denial of Service condition.
What is CVE-2021-0263?
The vulnerability affects the Multi-Service process on the FPC of Juniper Networks Junos OS on PTX Series devices. It can make the process unresponsive during heavy route churn, impacting traffic forwarding.
The Impact of CVE-2021-0263
Exploitation of this vulnerability can lead to a Denial of Service (DoS) condition, affecting the availability of services on the affected devices.
Technical Details of CVE-2021-0263
The vulnerability affects Junos OS versions on PTX Series prior to specific releases. An example configuration causing this issue involves flow monitoring and forwarding options.
Vulnerability Description
The Multi-Service Process can become unresponsive during heavy route churn, causing traffic forwarding issues on affected devices.
Affected Systems and Versions
Junos OS on PTX Series versions prior to specific releases are affected, while versions after the mentioned releases are secure.
Exploitation Mechanism
Malicious exploitation of this vulnerability has not been detected by Juniper SIRT.
Mitigation and Prevention
To safeguard against this vulnerability, updating Junos OS to the specified releases is recommended. Additionally, deactivating the sampling configuration under the chassis hierarchy can mitigate the issue.
Immediate Steps to Take
Update Junos OS to versions 18.2R3-S7, 18.3R3-S4, 18.4R2-S8, 18.4R3-S7, 19.1R3-S4, 19.2R3-S1, 19.3R3-S1, 19.4R2-S4, 19.4R3-S1, 20.1R2, 20.2R2, 20.3R1-S2, 20.3R2, 20.4R1, or later.
Long-Term Security Practices
Regularly updating software and monitoring for security advisories can help prevent such vulnerabilities in the long term.
Patching and Updates
Juniper Networks has released software updates to address this vulnerability.