CVE-2025-21590 in Junos OS
Summary
by MITRE • 03/12/2025
An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges to compromise the integrity of the device.
A local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device. This issue is not exploitable from the Junos CLI. This issue affects Junos OS:
* All versions before 21.2R3-S9, * 21.4 versions before 21.4R3-S10, * 22.2 versions before 22.2R3-S6, * 22.4 versions before 22.4R3-S6, * 23.2 versions before 23.2R2-S3, * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R1-S2, 24.2R2.
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Analysis
by VulDB Data Team • 03/18/2025
This vulnerability represents a critical improper isolation or compartmentalization flaw within the kernel of Juniper Networks Junos OS operating systems. The weakness stems from insufficient separation mechanisms that allow a local attacker with elevated privileges to bypass security boundaries and execute arbitrary code on the affected device. The vulnerability specifically targets the kernel level where privilege escalation occurs, creating a dangerous environment where legitimate administrative access can be leveraged for malicious purposes. This issue demonstrates a fundamental failure in the principle of least privilege and access control enforcement that should be maintained at the kernel level of any secure operating system.
The technical exploitation of this vulnerability occurs when a local attacker with shell access attempts to inject malicious code into the system. The improper compartmentalization allows the attacker to execute code that can compromise the device integrity, potentially leading to complete system compromise. This type of vulnerability falls under the CWE-276 category of improper privilege management and aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation'. The vulnerability is particularly concerning because it does not require network access or external exploitation vectors, making it a serious internal threat that can be leveraged by insiders or attackers who have already gained shell access to the system.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows for complete compromise of the device integrity. An attacker who successfully exploits this vulnerability could potentially modify system binaries, install backdoors, manipulate network configurations, or exfiltrate sensitive data from the device. The affected versions span multiple major releases of Junos OS, indicating this is a persistent issue that has not been adequately addressed in recent software versions. Organizations running these vulnerable versions face significant risk of unauthorized system modification and potential network disruption. The vulnerability affects not just individual devices but could potentially compromise entire network infrastructures if multiple devices are running vulnerable versions.
The mitigation strategy for this vulnerability requires immediate patching of all affected Junos OS versions to the recommended secure releases. Organizations should also implement strict access controls and monitoring for shell access to prevent unauthorized users from gaining the necessary privileges to exploit this vulnerability. Network segmentation and least privilege principles should be enforced to limit the potential impact of any successful exploitation. Additionally, regular security assessments and vulnerability scanning should be conducted to identify any other potential compartmentalization failures within the network infrastructure. The remediation process should include comprehensive testing of patches to ensure they do not introduce compatibility issues with existing network configurations while maintaining the security improvements necessary to protect against this specific vulnerability.