CVE-2018-0034 in Junos
Summary
by MITRE
A Denial of Service vulnerability exists in the Juniper Networks Junos OS JDHCPD daemon which allows an attacker to core the JDHCPD daemon by sending a crafted IPv6 packet to the system. This issue is limited to systems which receives IPv6 DHCP packets on a system configured for DHCP processing using the JDHCPD daemon. This issue does not affect IPv4 DHCP packet processing. Affected releases are Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S10 on EX Series; 12.3X48 versions prior to 12.3X48-D70 on SRX Series; 14.1X53 versions prior to 14.1X53-D47 on EX2200/VC, EX3200, EX3300/VC, EX4200, EX4300, EX4550/VC, EX4600, EX6200, EX8200/VC (XRE), QFX3500, QFX3600, QFX5100; 14.1X53 versions prior to 14.1X53-D130 on QFabric; 15.1 versions prior to 15.1R4-S9, 15.1R6-S6, 15.1R7; 15.1X49 versions prior to 15.1X49-D140 on SRX Series; 15.1X53 versions prior to 15.1X53-D67 on QFX10000 Series; 15.1X53 versions prior to 15.1X53-D233 on QFX5110, QFX5200; 15.1X53 versions prior to 15.1X53-D471 on NFX 150, NFX 250; 16.1 versions prior to 16.1R3-S9, 16.1R4-S8, 16.1R5-S4, 16.1R6-S3, 16.1R7; 16.2 versions prior to 16.2R2-S5, 16.2R3; 17.1 versions prior to 17.1R1-S7, 17.1R2-S7, 17.1R3; 17.2 versions prior to 17.2R1-S6, 17.2R2-S4, 17.2R3; 17.3 versions prior to 17.3R1-S4, 17.3R2-S2, 17.3R3; 17.4 versions prior to 17.4R1-S3, 17.4R2.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability described in CVE-2018-0034 represents a critical denial of service condition within Juniper Networks Junos OS systems that specifically affects the JDHCPD daemon responsible for processing IPv6 DHCP packets. This flaw enables remote attackers to cause the daemon to crash through the injection of specially crafted IPv6 packets, effectively disrupting network services and potentially compromising network availability. The vulnerability is particularly significant because it targets the core DHCP processing functionality that many network devices rely upon for dynamic IP address assignment and network configuration management. The issue is confined exclusively to systems configured to process IPv6 DHCP traffic using the JDHCPD daemon, meaning that IPv4 DHCP processing remains unaffected by this particular weakness.
The technical nature of this vulnerability stems from inadequate input validation within the JDHCPD daemon implementation, where the system fails to properly handle malformed or unexpected IPv6 packet structures. When the daemon encounters these crafted packets, it triggers a memory corruption condition that results in an immediate crash of the process. This behavior aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-248, which covers unspecified other issues in the context of improper input handling. The daemon's failure to properly validate packet headers and content leads to a state where memory pointers become corrupted, causing the process to terminate unexpectedly and requiring manual intervention or system restart to restore normal operation.
From an operational perspective, this vulnerability poses substantial risk to network infrastructure reliability and availability, particularly in environments where IPv6 DHCP services are actively utilized. Network administrators may experience unexpected service interruptions that could impact critical network operations, especially in data centers or enterprise environments where automatic IP address assignment is essential for device connectivity. The attack vector requires only the ability to send IPv6 packets to the affected system, making it accessible to remote attackers who may not require physical access or elevated privileges. This vulnerability effectively provides an easy path for denial of service attacks that can be executed with minimal technical expertise, potentially causing cascading failures in network infrastructure if multiple devices are affected simultaneously.
The mitigation strategy for this vulnerability involves applying the appropriate software patches provided by Juniper Networks, which typically include code modifications that enhance input validation and proper error handling within the JDHCPD daemon. Network administrators should prioritize patching affected systems, particularly those running versions prior to the specified release numbers mentioned in the vulnerability description. Additionally, implementing network segmentation and access controls to limit which systems can receive IPv6 DHCP packets can provide an additional layer of protection. Monitoring systems should be configured to detect unusual patterns of DHCP packet traffic that might indicate exploitation attempts, and network administrators should maintain regular vulnerability assessments to identify and remediate similar issues. The ATT&CK framework categorizes this vulnerability under T1499.004, which describes network denial of service attacks, and T1595.001, which covers network sniffing techniques that attackers might use to identify vulnerable systems. Organizations should also consider implementing intrusion detection systems that can identify and alert on malformed IPv6 DHCP packet patterns that could indicate exploitation attempts against this specific vulnerability.