CVE-2021-0217 : Vulnerability Insights and Analysis

A vulnerability in processing certain DHCP packets on Juniper Networks Junos OS running on EX Series and QFX Series switches can lead to a memory leak issue causing Denial of Service (DoS) attacks. The vulnerability affects multiple versions of Junos OS, leading to potential system instability due to memory exhaustion.

Understanding CVE-2021-0217

This CVE describes a vulnerability in Juniper Networks Junos OS impacting EX Series and QFX Series switches. By exploiting this issue, an attacker can cause a DoS condition by exhausting the system's DMA memory.

What is CVE-2021-0217?

A vulnerability in processing DHCP packets on Juniper Networks Junos OS running on EX Series and QFX Series switches may exhaust DMA memory, leading to a DoS condition. Following specific DHCP packet processing, the system may become unstable as DMA memory utilization reaches critical levels.

The Impact of CVE-2021-0217

The vulnerability can result in a Denial of Service (DoS) condition on affected devices. Exploitation of this issue may lead to traffic disruptions or crashing of the fxpc process, impacting network functionality and stability.

Technical Details of CVE-2021-0217

The vulnerability affects Juniper Networks Junos OS versions in the EX Series and QFX Series. Systems running specific versions prior to the patched releases are vulnerable to memory leak issues when processing certain DHCP packets.

Vulnerability Description

Processing of certain DHCP packets on affected switches may exhaust DMA memory, causing system instability and potential DoS conditions. Exploitation of this vulnerability can impact network traffic forwarding and overall system performance.

Affected Systems and Versions

Junos OS versions including 17.4R3-S3, 18.1R3-S11, 18.2R3-S6, 18.3R3-S4, 18.4R2-S5, 18.4R3-S6, 19.1R1-S6, 19.1R3-S3, 19.2R3-S1, 19.3R2-S5, 19.3R3, 19.4R2-S2, 19.4R3, 20.1R2, and 20.2R2, among others are affected by this vulnerability.

Exploitation Mechanism

The vulnerability is triggered by processing specific DHCP packets from adjacent clients on EX Series and QFX Series switches. Upon exploitation, DMA memory exhaustion occurs, leading to system instability and potential DoS conditions.

Mitigation and Prevention

To address CVE-2021-0217, Juniper Networks has released updated software versions to resolve the memory leak issue and prevent potential DoS attacks on affected devices.

Immediate Steps to Take

Deploy the recommended software releases, including Junos OS 17.4R3-S3, 18.1R3-S11, 18.2R3-S6, 18.3R3-S4, 18.4R2-S5, 18.4R2-S7, 18.4R3-S6, 19.1R1-S6, 19.1R3-S3, 19.2R3-S1, 19.3R2-S5, 19.3R3, 19.4R2-S2, 19.4R3, 20.1R2, 20.2R1-S2, 20.2R2, 20.3R1, or later releases to mitigate the vulnerability.

Long-Term Security Practices

Regularly update Junos OS software to the latest patched versions to address security vulnerabilities and enhance network resilience against potential threats.

Patching and Updates

Juniper Networks advises applying the provided software updates to safeguard against the memory leak issue and prevent potential denial of service attacks on affected Junos OS devices.