CVE-2022-22160 in Junos OS
Summary
by MITRE • 01/19/2022
An Unchecked Error Condition vulnerability in the subscriber management daemon (smgd) of Juniper Networks Junos OS allows an unauthenticated adjacent attacker to cause a crash of and thereby a Denial of Service (DoS). In a subscriber management / broadband edge environment if a single session group configuration contains dual-stack and a pp0 interface, smgd will crash and restart every time a PPPoE client sends a specific message. This issue affects Juniper Networks Junos OS on MX Series: 16.1 version 16.1R1 and later versions prior to 18.4R3-S10; 19.1 versions prior to 19.1R2-S3, 19.1R3-S7; 19.2 versions prior to 19.2R1-S8, 19.2R3-S4; 19.3 versions prior to 19.3R3-S4; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R3-S3; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S2; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R2. This issue does not affect Juniper Networks Junos OS versions prior to 16.1R1.
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Analysis
by VulDB Data Team • 01/20/2022
The vulnerability described in CVE-2022-22160 represents a critical unchecked error condition within the subscriber management daemon (smgd) of Juniper Networks Junos OS operating systems. This flaw specifically targets broadband edge environments where subscriber management functions are critical for maintaining network connectivity and service delivery. The issue manifests when a single session group configuration contains both dual-stack addressing and a pp0 interface, creating a scenario where the daemon becomes vulnerable to controlled crashes through specific PPPoE client messages. The vulnerability's impact extends across multiple Junos OS version lines, affecting releases from 16.1R1 through 21.2R2, with specific patches required for each affected version range.
The technical nature of this vulnerability stems from insufficient error handling within the smgd process, which fails to properly validate incoming PPPoE messages when processing dual-stack configurations with pp0 interfaces. This unchecked error condition allows an adjacent attacker to send specifically crafted messages that trigger a crash in the subscriber management daemon. The daemon's restart mechanism creates a continuous DoS loop where the system repeatedly crashes and restarts, effectively denying legitimate network services to subscribers. This behavior aligns with CWE-459, which describes "Incomplete Cleanup" vulnerabilities where error conditions are not properly handled, and represents a classic example of how improper error handling can lead to system instability and availability issues.
From an operational standpoint, this vulnerability poses significant risks to network service availability and customer satisfaction in broadband environments where subscriber management is crucial. The DoS condition affects the entire subscriber management functionality, potentially impacting thousands of concurrent users simultaneously. The requirement for an adjacent attacker means that physical proximity to the network infrastructure is necessary, but this limitation does not reduce the severity of impact. Network administrators must understand that even limited physical access can result in substantial service disruption, particularly in environments where service level agreements require high availability. This vulnerability particularly affects service provider networks where maintaining continuous subscriber connectivity is paramount for business operations and revenue generation.
The mitigation strategy for CVE-2022-22160 requires immediate implementation of vendor-provided patches across all affected Junos OS versions. Network administrators should prioritize patching operations, particularly in production environments where subscriber management functions are actively utilized. The patching process should include thorough testing in staging environments before deployment to production networks to ensure no unintended side effects occur. Additionally, network segmentation and access control measures should be reviewed to minimize the attack surface, ensuring that only authorized personnel have physical access to affected network equipment. Organizations should also implement monitoring solutions to detect unusual patterns in subscriber management daemon behavior, as early detection can help identify potential exploitation attempts. The vulnerability's classification under ATT&CK technique T1499.004 for "Endpoint Denial of Service" emphasizes the need for robust endpoint protection and monitoring capabilities to detect and respond to such attacks effectively.
This vulnerability demonstrates the critical importance of proper error handling in network management daemons and highlights the potential for seemingly minor configuration combinations to create significant security and operational risks. The specific combination of dual-stack configuration with pp0 interface creates a unique scenario that was not adequately addressed in the original software implementation, indicating a gap in testing procedures for edge cases in subscriber management functionality. The impact extends beyond simple service disruption to potentially affecting revenue generation for service providers who rely on continuous subscriber connectivity for their business operations. Organizations should conduct comprehensive vulnerability assessments to identify similar unchecked error conditions in other network management components and implement systematic approaches to error handling that prevent cascading failures in critical network services.