CVE-2023-44203 in Junos OS
Summary
by MITRE • 10/25/2023
An Improper Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600 allows a adjacent attacker to send specific traffic, which leads to packet flooding, resulting in a Denial of Service (DoS).
When a specific IGMP packet is received in an isolated VLAN, it is duplicated to all other ports under the primary VLAN, which causes a flood.
This issue affects QFX5000 series, EX2300, EX3400, EX4100, EX4400 and EX4600 platforms only.
This issue affects Juniper Junos OS on on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600:
* All versions prior to 20.4R3-S5; * 21.1 versions prior to 21.1R3-S4; * 21.2 versions prior to 21.2R3-S3; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S2; * 22.1 versions prior to 22.1R3; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2.
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Analysis
by VulDB Data Team • 10/25/2023
The vulnerability described in CVE-2023-44203 represents a critical flaw in the Packet Forwarding Engine of Juniper Networks Junos OS affecting specific hardware platforms including QFX5000 Series, EX2300, EX3400, EX4100, EX4400, and EX4600 devices. This issue stems from improper handling of exceptional conditions within the network forwarding logic, specifically when processing Internet Group Management Protocol (IGMP) packets in isolated virtual LAN environments. The vulnerability manifests when an adjacent attacker crafts and sends specific IGMP traffic to a device operating within an isolated VLAN configuration, triggering a cascading effect that results in packet flooding across the network infrastructure. The technical implementation flaw lies in the failure of the PFE to properly validate or process exceptional conditions that occur during IGMP packet handling, leading to an unintended behavior where packets are erroneously duplicated and forwarded to all ports within the primary VLAN instead of being properly contained within the isolated VLAN segment.
The operational impact of this vulnerability is severe and directly translates to a denial of service condition that can effectively disrupt network operations across affected platforms. When the malicious IGMP packet is processed, the system's packet forwarding logic fails to properly isolate the traffic within the designated VLAN boundaries, causing the packet duplication mechanism to propagate traffic indiscriminately across all ports in the primary VLAN. This creates a massive flood of packets that overwhelms network resources and can lead to complete service disruption for legitimate network traffic. The vulnerability's exploitability is limited to adjacent network positions since it requires physical proximity to the target device to send the crafted traffic, but this adjacency requirement does not mitigate the potential damage. Network administrators must understand that this vulnerability can be exploited to create network outages that affect not only the immediate device but potentially entire network segments depending on the scale of the flooding effect. The issue affects multiple software versions across different Junos OS release branches, creating a broad impact surface that requires careful version management and patch deployment across affected network infrastructure.
The root cause of this vulnerability aligns with CWE-703, which describes improper handling of exceptional conditions in software systems, and specifically relates to improper handling of exceptional conditions in network packet processing. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1498.001 which involves network denial of service attacks. The attack vector requires an adjacent network position and involves sending specifically crafted IGMP packets that trigger the flawed packet forwarding logic. The vulnerability demonstrates a classic case of insufficient input validation and error handling within network device firmware, where exceptional conditions during packet processing are not properly managed, leading to unintended behavior that can be exploited for service disruption. Organizations should consider this vulnerability as part of their broader network security posture assessment, particularly in environments where network segmentation is critical for security isolation. The vulnerability's presence across multiple Junos OS versions indicates a systemic issue in the packet forwarding engine implementation that affects the fundamental reliability of network operations across the affected platform families. Security teams must prioritize patching this vulnerability across all affected devices, as the potential for disruption extends beyond simple network performance degradation to complete service outages that can impact business operations and customer connectivity. The recommended mitigation involves upgrading to the patched versions of Junos OS as specified in the vendor advisories, ensuring that all network infrastructure components are updated to versions that contain the necessary fixes for proper exception handling in IGMP packet processing.