CVE-2016-1277 in Junos
Summary
by MITRE
Juniper Junos OS before 12.1X46-D50, 12.1X47 before 12.1X47-D40, 12.3X48 before 12.3X48-D30, 13.3 before 13.3R9, 14.1 before 14.1R8, 14.1X53 before 14.1X53-D40, 14.2 before 14.2R6, 15.1 before 15.1F6 or 15.1R3, and 15.1X49 before 15.1X49-D40, when configured with a GRE or IPIP tunnel, allow remote attackers to cause a denial of service (kernel panic) via a crafted ICMP packet.
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Analysis
by VulDB Data Team • 09/02/2022
This vulnerability affects Juniper Junos OS versions prior to specific release thresholds and represents a critical denial of service flaw that can be exploited remotely through crafted ICMP packets targeting systems configured with GRE or IPIP tunnels. The issue stems from insufficient input validation within the kernel processing of tunnel traffic, specifically when handling malformed ICMP packets that trigger kernel panic conditions. The vulnerability impacts network infrastructure devices running Junos OS where GRE (Generic Routing Encapsulation) or IPIP (IP in IP) tunneling protocols are enabled, creating a significant operational risk for network availability.
The technical flaw manifests in the kernel's handling of ICMP packet processing within tunnel contexts where the system fails to properly validate packet headers and payload structures. When a remote attacker sends specially crafted ICMP packets to a vulnerable device, the kernel's tunnel processing module encounters malformed data that causes it to crash or panic, resulting in complete service disruption. This behavior aligns with CWE-129, which addresses improper validation of input boundaries, and represents a classic example of a buffer overflow or memory corruption vulnerability within network kernel modules. The vulnerability specifically affects the tunneling subsystem where ICMP packets are processed in the context of GRE or IPIP tunnel interfaces, making it particularly dangerous for network devices that rely on these encapsulation protocols for traffic forwarding.
The operational impact of this vulnerability extends beyond simple service disruption as it can affect critical network infrastructure components including routers, firewalls, and other network devices that utilize tunneling for traffic management or secure communications. Network administrators may experience unexpected outages, service degradation, or complete loss of network connectivity when attackers exploit this vulnerability, particularly in environments where GRE or IPIP tunnels are commonly deployed for site-to-site connections, MPLS traffic engineering, or VPN implementations. The remote nature of the attack means that adversaries can exploit this vulnerability from outside the network perimeter without requiring authentication or physical access, making it particularly dangerous for internet-facing network devices.
Mitigation strategies should focus on immediate patching of affected Junos OS versions to the recommended secure releases, which include all versions listed in the CVE description. Network administrators should also implement temporary network segmentation or access controls to limit exposure while patches are deployed. Additional defensive measures include monitoring for unusual ICMP traffic patterns and implementing network-based intrusion detection systems to identify potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique for network denial of service attacks, and organizations should consider implementing network traffic filtering rules to prevent malformed ICMP packets from reaching vulnerable devices. The vulnerability also highlights the importance of proper input validation in network kernel modules and demonstrates the need for comprehensive security testing of network infrastructure firmware to prevent similar issues in the future.