CVE-2018-0017 in Junos
Summary
by MITRE
A vulnerability in the Network Address Translation - Protocol Translation (NAT-PT) feature of Junos OS on SRX series devices may allow a certain valid IPv6 packet to crash the flowd daemon. Repeated crashes of the flowd daemon can result in an extended denial of service condition for the SRX device. Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D72; 12.3X48 versions prior to 12.3X48-D55; 15.1X49 versions prior to 15.1X49-D90.
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Analysis
by VulDB Data Team • 02/27/2023
The vulnerability described in CVE-2018-0017 represents a critical flaw in the Network Address Translation-Protocol Translation (NAT-PT) functionality of Juniper Networks SRX series devices running specific versions of Junos OS. This issue specifically targets the flowd daemon, which is responsible for flow logging and monitoring within the network infrastructure. The vulnerability manifests when processing certain valid IPv6 packets that contain malformed or unexpected data structures within the NAT-PT translation process, leading to unpredictable behavior and system instability. The affected device families include SRX series appliances running Junos OS versions 12.1X46 prior to 12.1X46-D72, 12.3X48 prior to 12.3X48-D55, and 15.1X49 prior to 15.1X49-D90, indicating a widespread impact across multiple release branches of the operating system.
The technical nature of this vulnerability stems from insufficient input validation within the flowd daemon's packet processing routines when handling IPv6 packets that traverse the NAT-PT translation mechanism. This flaw creates a condition where legitimate network traffic can trigger a buffer overflow or memory corruption scenario, causing the daemon to crash unexpectedly. The root cause aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read vulnerabilities. The vulnerability operates at the network protocol level, specifically within the IPv6 to IPv4 translation process, making it particularly dangerous as it can be exploited through normal network operations without requiring special privileges or authentication.
The operational impact of CVE-2018-0017 extends beyond simple service disruption, creating a sustained denial of service condition that can severely compromise network availability and reliability. When the flowd daemon crashes repeatedly, it not only affects flow logging capabilities but also potentially impacts other network services that depend on proper flow tracking and monitoring. This vulnerability can be particularly devastating in enterprise environments where SRX devices serve as critical network security gateways, as it can lead to complete loss of visibility into network traffic patterns and potential security events. The repeated nature of the crashes means that even a single malicious packet can cause extended downtime, making this vulnerability particularly attractive to attackers seeking to disrupt network operations.
Mitigation strategies for CVE-2018-0017 should prioritize immediate patch deployment to the affected Junos OS versions, with the specific recommended patches being 12.1X46-D72, 12.3X48-D55, and 15.1X49-D90 for their respective affected branches. Network administrators should also consider disabling NAT-PT functionality entirely if it is not essential for their network operations, as this removes the attack surface entirely. Additionally, implementing network monitoring solutions that can detect and alert on flowd daemon crashes or abnormal traffic patterns can provide early warning of potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and T1566, which covers spearphishing attacks that could potentially leverage this vulnerability to gain network access. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of any successful exploitation attempts.