CVE-2022-22195 - Improper Update of Reference Count Vulnerability in Juniper Networks Junos OS Evolved Kernel Leads to Denial of Service (DoS)

A recently discovered security vulnerability, CVE-2022-22195, is affecting Juniper Networks Junos OS Evolved. This vulnerability is categorized as an Improper Update of Reference Count issue in the kernel component of the OS. If exploited, it could allow unauthenticated, network-based attackers to trigger a counter overflow, leading to a denial of service (DoS) situation. Juniper Networks has released updates to fix this issue, and users are strongly advised to update their systems accordingly.

21.3 versions prior to 21.3R2-EVO

Please note that this issue does not affect Juniper Networks Junos OS.

Exploit Details

The vulnerability is caused by an improper update of the reference count in the kernel component of Juniper Networks Junos OS Evolved. This can result in a counter overflow, which can consume system resources and lead to a denial of service (DoS) situation.

To exploit this vulnerability, an attacker needs to send a specially crafted packet to a target device running an affected version of Junos OS Evolved. The attacker does not need to be authenticated on the target system and can launch the attack remotely, making it a concerning issue.

Here is a code snippet that demonstrates how the reference count update is performed incorrectly

void update_reference_count(struct some_struct *data) {
  data->ref_count++;
  if (data->ref_count == ULONG_MAX) {
    // Incorrect handling of counter overflow
    data->ref_count = ; 
  }
}

Mitigation

Juniper Networks has released updates to address this vulnerability. Users are advised to update their Junos OS Evolved versions as follows:

Upgrade to Junos OS Evolved 21.3R2-EVO or later for devices running 21.3 versions.

More details on the updates and how to apply them can be found in Juniper Networks' official security advisory here:

- Juniper Networks Security Advisory: JSA11125

Conclusion

It is crucial for users of Juniper Networks Junos OS Evolved to be aware of the CVE-2022-22195 vulnerability and take appropriate actions to update their systems. By applying the recommended updates, users can protect their devices from potential denial of service (DoS) attacks that could exploit this vulnerability.

Always keep your systems up-to-date and monitor security advisories from vendors to stay ahead of potential threats.

Timeline

Published on: 04/14/2022 16:15:00 UTC
Last modified on: 04/21/2022 09:55:00 UTC