CVE-2021-0210 in Junos
Summary
by MITRE • 01/16/2021
An Information Exposure vulnerability in J-Web of Juniper Networks Junos OS allows an unauthenticated attacker to elevate their privileges over the target system through opportunistic use of an authenticated users session. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S17; 17.3 versions prior to 17.3R3-S10; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.3 versions prior to 18.3R2-S4, 18.3R3-S4; 18.4 versions prior to 18.4R2-S5, 18.4R3-S5; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3; 19.2 versions prior to 19.2R1-S5, 19.2R3, 19.2R3-S1; 19.3 versions prior to 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2-S2, 19.4R3; 20.1 versions prior to 20.1R1-S4, 20.1R2; 20.2 versions prior to 20.2R1-S1, 20.2R2.
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Analysis
by VulDB Data Team • 02/14/2021
The vulnerability described in CVE-2021-0210 represents a critical information exposure flaw within Juniper Networks Junos OS J-Web interface that enables unauthenticated attackers to escalate privileges through session hijacking techniques. This vulnerability specifically targets the web-based management interface of Junos OS devices, creating a pathway for attackers to exploit authenticated user sessions without prior authentication credentials. The flaw stems from improper session management mechanisms that fail to adequately validate session tokens or implement sufficient session isolation controls, allowing malicious actors to leverage existing authenticated sessions for unauthorized system access. Such vulnerabilities are particularly dangerous in network infrastructure environments where administrative access can provide extensive control over network operations and security policies.
The technical implementation of this vulnerability involves the exploitation of session token handling within the J-Web management interface, where session identifiers are not properly validated or refreshed upon certain operations. Attackers can observe and potentially manipulate session cookies or tokens that are used to maintain user authentication state, enabling them to impersonate legitimate users and gain elevated privileges. This issue falls under the CWE-200 category of Information Exposure, specifically relating to improper handling of session identifiers and authentication tokens. The vulnerability demonstrates a fundamental weakness in the authentication and session management protocols implemented within the Junos OS web interface, where session state information is not adequately protected against unauthorized access or manipulation.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential complete system compromise and network infrastructure disruption. An attacker who successfully exploits this vulnerability can execute administrative commands, modify network configurations, access sensitive network data, and potentially establish persistent access points within the network environment. The vulnerability affects multiple major versions of Junos OS across different release branches, indicating a widespread issue that has persisted across several years of development cycles. This broad impact affects organizations running various Junos OS versions, from legacy 12.3 releases to more recent 20.2 versions, making it a critical concern for network security teams managing Juniper infrastructure across enterprise and service provider environments.
Organizations affected by this vulnerability should prioritize immediate remediation through the application of official Juniper security patches and updates for all impacted versions. The recommended mitigation strategy includes implementing network segmentation to limit access to management interfaces, deploying additional authentication controls such as two-factor authentication, and monitoring for suspicious session activity or unauthorized access attempts. Security teams should also consider implementing network access control lists to restrict access to J-Web interfaces from untrusted networks and establish robust logging and monitoring of administrative activities. This vulnerability aligns with ATT&CK technique T1078 for Valid Accounts and T1566 for Phishing, as it enables attackers to leverage existing authenticated sessions to maintain persistent access and potentially expand their attack surface through the compromised management interface. The vulnerability represents a significant risk to network security posture and requires immediate attention from security administrators to prevent potential exploitation and maintain the integrity of network infrastructure.