CVE-2015-5358 in NetBSD
Summary
by MITRE
Juniper Junos OS 12.1X44 before 12.1X44-D50, 12.1X46 before 12.1X46-D35, 12.1X47 before 12.1X47-D25, 12.3 before 12.3R9, 12.3X48 before 12.3X48-D15, 13.2 before 13.2R7, 13.2X51 before 13.2X51-D35, 13.2X52 before 13.2X52-D25, 13.3 before 13.3R6, 14.1R3 before 14.1R3-S2, 14.1 before 14.1R4, 14.1X53 before 14.1X53-D12, 14.1X53 before 14.1X53-D16, 14.1X55 before 14.1X55-D25, 14.2 before 14.2R2, and 15.1 before 15.1R1 allows remote attackers to cause a denial of service (mbuf and connection consumption and restart) via a large number of requests that trigger a TCP connection to move to the LAST_ACK state when there is more data to send.
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Analysis
by VulDB Data Team • 06/23/2022
This vulnerability affects Juniper Junos OS versions across multiple release branches including 12.1X44, 12.3, 12.3X48, 13.2, 13.2X51, 13.2X52, 13.3, 14.1R3, 14.1, 14.1X53, 14.1X55, 14.2, and 15.1, representing a significant exposure across the Juniper networking infrastructure ecosystem. The flaw manifests as a denial of service condition that specifically targets the network stack's handling of TCP connections in the LAST_ACK state, where the system processes multiple requests that exceed the available mbuf resources and connection tracking capacity. This vulnerability is categorized under CWE-400 as an unspecified resource management issue, specifically related to memory buffer exhaustion and connection table overflow.
The technical mechanism behind this vulnerability involves the improper handling of TCP connection state transitions within the kernel's network processing layer. When numerous requests are processed concurrently, the system attempts to establish TCP connections that enter the LAST_ACK state but contain additional data to transmit. This scenario causes the system to consume excessive memory buffers and connection tracking resources, leading to resource exhaustion and subsequent system instability. The attack vector requires remote exploitation through a large volume of crafted requests that trigger the specific connection state behavior, making it particularly dangerous in high-traffic network environments where legitimate traffic can be disrupted by malicious actors.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively render network devices unavailable to legitimate users while potentially consuming system resources to the point of complete restart. Network administrators face the challenge of maintaining service availability when attackers can deliberately exhaust system resources through this specific TCP state handling flaw. The vulnerability's presence across multiple Junos OS versions indicates a fundamental issue in the network stack implementation that affects a substantial portion of Juniper's deployed infrastructure, potentially impacting enterprise networks, service providers, and critical infrastructure components that rely on Juniper networking equipment.
Mitigation strategies should focus on implementing immediate software updates to the patched versions specified in the CVE advisory, which address the underlying TCP connection handling logic. Network segmentation and rate limiting mechanisms can provide temporary protection by limiting the volume of requests that can trigger the vulnerable code path. Additionally, monitoring for unusual connection state patterns and mbuf consumption spikes can help detect exploitation attempts. The vulnerability's classification under ATT&CK technique T1499.004 for network denial of service highlights the importance of implementing robust network monitoring and intrusion detection systems to identify and respond to such attacks. Organizations should also consider implementing connection tracking limits and resource allocation controls to prevent complete system exhaustion, while maintaining comprehensive backup and recovery procedures for network infrastructure components that may be affected by this vulnerability.