CVE-2023-44204 in Junos OS
Summary
by MITRE • 10/25/2023
An Improper Validation of Syntactic Correctness of Input vulnerability in Routing Protocol Daemon (rpd) Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based attacker to cause a Denial of Service (DoS).
When a malformed BGP UPDATE packet is received over an established BGP session, the rpd crashes and restarts.
This issue affects both eBGP and iBGP implementations.
This issue affects:
Juniper Networks Junos OS
* 21.4 versions prior to 21.4R3-S4; * 22.1 versions prior to 22.1R3-S3; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2-S1, 22.4R3; * 23.2 versions prior to 23.2R1, 23.2R2;
Juniper Networks Junos OS Evolved
* 21.4 versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S3-EVO; * 22.2 versions prior to 22.2R3-S3-EVO; * 22.3 versions prior to 22.3R2-S2-EVO; * 22.4 versions prior to 22.4R3-EVO; * 23.2 versions prior to 23.2R2-EVO;
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Analysis
by VulDB Data Team • 10/25/2023
The vulnerability identified as CVE-2023-44204 represents a critical weakness in the Routing Protocol Daemon (rpd) component of Juniper Networks Junos OS and Junos OS Evolved platforms. This issue manifests as an improper validation of syntactic correctness of input, specifically when processing BGP UPDATE packets that are malformed in structure or content. The vulnerability operates at the network protocol level where BGP (Border Gateway Protocol) is used for routing between autonomous systems, making it a significant concern for network infrastructure security and stability. The flaw exists within the input validation mechanisms that should normally ensure proper packet formatting before processing, but fails to adequately validate the syntactic structure of incoming BGP messages.
The technical exploitation of this vulnerability occurs when an unauthenticated attacker sends a malformed BGP UPDATE packet over an established BGP session to a vulnerable Junos OS device. This attack vector is particularly dangerous because it requires no authentication credentials and can be executed from any network location that can reach the target device. Upon receiving such a malformed packet, the rpd process crashes and subsequently restarts, causing an immediate disruption to routing services. This crash-restart cycle represents a classic denial of service condition where legitimate network traffic is interrupted, and routing information becomes unavailable to other network devices that depend on the affected system for path determination.
The operational impact of this vulnerability extends beyond simple service interruption to potentially compromise network stability and availability. When the rpd daemon crashes and restarts, it affects both eBGP (external BGP) and iBGP (internal BGP) implementations, meaning that the vulnerability impacts routing operations across the entire autonomous system. The restart process can cause temporary loss of connectivity, route flapping, and disruption of network services that depend on stable routing information. Network operators may experience significant downtime as routing tables rebuild and convergence occurs, particularly in large networks where multiple devices rely on the affected system for routing decisions.
Network security professionals should recognize this vulnerability as a manifestation of CWE-20, Improper Input Validation, which is a fundamental weakness in input sanitization and validation processes. The attack pattern aligns with techniques described in MITRE ATT&CK framework under T1499.004 - Endpoint Denial of Service, where attackers target network services to cause disruption. Organizations running affected Junos OS versions should implement immediate mitigations including applying the latest security patches, implementing network access controls to restrict BGP session establishment, and monitoring for unusual BGP packet patterns. Additionally, network segmentation and BGP session filtering can help reduce the attack surface and limit potential impact from such attacks. The vulnerability affects multiple major release lines of Junos OS, emphasizing the widespread nature of this issue across different versions and highlighting the importance of maintaining current security patches for network infrastructure devices.