CVE-2021-0208 : Security Advisory and Response
Learn about CVE-2021-0208, an improper input validation vulnerability in Juniper Networks Junos OS that allows for Denial of Service attacks. Find out the impacted systems, exploitation details, and mitigation steps.
An improper input validation vulnerability in the Routing Protocol Daemon (RPD) service of Juniper Networks Junos OS allows an attacker to send a malformed RSVP packet when bidirectional LSPs are in use, leading to a Denial of Service (DoS) condition. This vulnerability affects various versions of Junos OS and Junos OS Evolved.
Understanding CVE-2021-0208
This CVE highlights a specific vulnerability in Juniper Networks Junos OS that can be exploited to trigger a Denial of Service (DoS) attack under certain conditions.
What is CVE-2021-0208?
CVE-2021-0208 refers to an improper input validation vulnerability in the RPD service of Juniper Networks Junos OS that enables malicious actors to crash the RPD on an egress router, causing a sustained DoS condition.
The Impact of CVE-2021-0208
The impact of this vulnerability is significant, as it allows attackers to disrupt network operations by leveraging malformed RSVP packets, leading to a denial of service state.
Technical Details of CVE-2021-0208
This section delves into the technical specifics of the vulnerability, including the description, affected systems, and the exploitation mechanism.
Vulnerability Description
The vulnerability originates from improper input validation in the RPD service, enabling the crashing of the RPD on an egress router through the receipt of malformed RSVP packets.
Affected Systems and Versions
Juniper Networks Junos OS versions are impacted, including 17.3R3-S10 and all versions prior to this, except for specific versions such as 15.1X49-D240 for SRX Series.
Exploitation Mechanism
The vulnerability can be exploited when bidirectional LSPs are active in the network, allowing attackers to sustain a DoS state by continuously sending malformed RSVP packets.
Mitigation and Prevention
To address CVE-2021-0208, users are advised to take immediate action and adopt long-term security practices to protect their systems.
Immediate Steps to Take
Implement workarounds like disabling RSVP for specific interfaces if bidirectional LSPs are operational in the network.
Long-Term Security Practices
Ensure systems are updated with the latest software releases that address the vulnerability to prevent future exploitation.
Patching and Updates
Juniper Networks has released updated software versions that resolve the issue. Ensure your systems are updated with the recommended releases to mitigate the risk of exploitation.