CVE-2023-44201 in Junos OS
Summary
by MITRE • 10/25/2023
An Incorrect Permission Assignment for Critical Resource vulnerability in a specific file of Juniper Networks Junos OS and Junos OS Evolved allows a local authenticated attacker to read configuration changes without having the permissions.
When a user with the respective permissions commits a configuration change, a specific file is created. That file is readable even by users with no permissions to access the configuration. This can lead to privilege escalation as the user can read the password hash when a password change is being committed.
This issue affects:
Juniper Networks Junos OS
* All versions prior to 20.4R3-S4; * 21.1 versions prior to 21.1R3-S4; * 21.2 versions prior to 21.2R3-S2; * 21.3 versions prior to 21.3R2-S2, 21.3R3-S1; * 21.4 versions prior to 21.4R2-S1, 21.4R3.
Juniper Networks Junos OS Evolved
* All versions prior to 20.4R3-S4-EVO; * 21.1 versions prior to 21.1R3-S2-EVO; * 21.2 versions prior to 21.2R3-S2-EVO; * 21.3 versions prior to 21.3R3-S1-EVO; * 21.4 versions prior to 21.4R2-S2-EVO.
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Analysis
by VulDB Data Team • 10/31/2023
This vulnerability represents a critical misconfiguration issue in Juniper Networks Junos OS and Junos OS Evolved platforms where improper file permissions create a pathway for unauthorized information disclosure. The flaw manifests when configuration changes are committed through the system, resulting in the creation of a specific file that contains sensitive data including password hashes. This file is accessible to users who lack proper authorization to view configuration information, effectively bypassing the intended access controls. The vulnerability falls under CWE-732 which specifically addresses Incorrect Permission Assignment for Critical Resources, making it a direct violation of fundamental security principles that govern access control mechanisms within network operating systems. The issue is particularly concerning because it operates at the local authentication level where legitimate users with minimal privileges can exploit this weakness to gain elevated information access.
The technical implementation of this vulnerability stems from the improper assignment of file permissions during the configuration commit process within the Junos OS architecture. When a user with appropriate permissions executes a configuration change that includes password modifications, the system generates a temporary file containing the password hash as part of the commit transaction. This file is created with insufficiently restrictive permissions, allowing any local authenticated user to read its contents regardless of their privilege level or role within the system. The flaw essentially creates a temporary backdoor where sensitive authentication data becomes exposed to unauthorized parties, enabling potential attackers to extract password hashes and subsequently attempt credential compromise through offline password cracking attacks or pass-the-hash techniques. This misconfiguration directly impacts the principle of least privilege and violates standard security practices that require strict access controls on sensitive system files.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable privilege escalation and credential compromise within affected networks. An attacker exploiting this vulnerability can extract password hashes from configuration change files, which may then be used to conduct dictionary attacks, brute force attempts, or other credential-based attacks against the system. This threat is particularly significant in enterprise environments where Junos OS devices serve as core network infrastructure components, as compromised credentials could lead to unauthorized access to network devices, configuration modifications, and potential lateral movement within the network. The vulnerability affects multiple release branches of Juniper's operating systems, indicating it is not an isolated incident but rather a systemic issue that has persisted across various versions and releases, making it a widespread concern for organizations maintaining legacy systems.
Organizations affected by this vulnerability should immediately implement the recommended security patches provided by Juniper Networks, specifically targeting the version ranges mentioned in the advisory. The patching process should be prioritized across all affected Junos OS and Junos OS Evolved installations, with particular attention to critical network infrastructure devices. Additionally, system administrators should conduct immediate audits of file permissions on affected systems to ensure that no unauthorized users have access to configuration change files, and should implement monitoring solutions to detect unauthorized access attempts to sensitive system files. This vulnerability aligns with several ATT&CK techniques including T1566 for credential access and T1078 for valid accounts, making it a significant concern for organizations implementing comprehensive threat detection strategies. Organizations should also review their local authentication policies and implement additional monitoring measures to detect anomalous access patterns that might indicate exploitation attempts. The remediation process should include verification that the patched versions properly enforce access controls and that no residual files with improper permissions remain on the system, ensuring complete mitigation of the vulnerability across all affected network infrastructure components.