Juniper Networks Junos OS Evolved SSH Daemon release of resource

Summaryinfo

A vulnerability has been found in Juniper Networks Junos OS Evolved and classified as critical. The impacted element is an unknown function of the component SSH Daemon. Performing a manipulation results in release of resource. This vulnerability was named CVE-2024-39562. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Juniper Networks Junos OS Evolved. It has been classified as critical. This affects an unknown part of the component SSH Daemon. The manipulation with an unknown input leads to a release of resource vulnerability. CWE is classifying the issue as CWE-772. The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. This is going to have an impact on availability. The summary by CVE is:

A Missing Release of Resource after Effective Lifetime vulnerability the xinetd process, responsible for spawning SSH daemon (sshd) instances, of Juniper Networks Junos OS Evolved allows an unauthenticated network-based attacker to cause a Denial of Service (DoS) by blocking SSH access for legitimate users. Continued receipt of these connections will create a sustained Denial of Service (DoS) condition. The issue is triggered when a high rate of concurrent SSH requests are received and terminated in a specific way, causing xinetd to crash, and leaving defunct sshd processes. Successful exploitation of this vulnerability blocks both SSH access as well as services which rely upon SSH, such as SFTP, and Netconf over SSH. Once the system is in this state, legitimate users will be unable to SSH to the device until service is manually restored.  See WORKAROUND section below. Administrators can monitor an increase in defunct sshd processes by utilizing the CLI command:   > show system processes | match sshd   root   25219 30901 0 Jul16 ?       00:00:00 [sshd] This issue affects Juniper Networks Junos OS Evolved: * All versions prior to 21.4R3-S7-EVO * 22.3-EVO versions prior to 22.3R2-S2-EVO, 22.3R3-S2-EVO; * 22.4-EVO versions prior to 22.4R3-EVO; * 23.2-EVO versions prior to 23.2R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved 22.1-EVO nor 22.2-EVO.

The advisory is shared at supportportal.juniper.net. This vulnerability is uniquely identified as CVE-2024-39562 since 06/25/2024. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 310757 (Juniper Junos OS Vulnerability (JSA75724)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 21.4R3-S7-EVO, 22.3R2-S2-EVO, 22.3R3-S2-EVO, 22.4R3-EVO or 23.2R2-EVO eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (310757). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• Juniper Networks

Name

• Junos OS Evolved

License

• commercial

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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