CVE-2020-1628 in Junos
Summary
by MITRE
Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discovered that packets utilizing these IP addresses may egress an EX4300 switch, leaking configuration information such as heartbeats, kernel versions, etc. out to the Internet, leading to an information exposure vulnerability. This issue affects Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D53 on EX4300; 15.1 versions prior to 15.1R7-S6 on EX4300; 15.1X49 versions prior to 15.1X49-D200, 15.1X49-D210 on EX4300; 16.1 versions prior to 16.1R7-S7 on EX4300; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2 on EX4300; 17.2 versions prior to 17.2R3-S3 on EX4300; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7 on EX4300; 17.4 versions prior to 17.4R2-S9, 17.4R3 on EX4300; 18.1 versions prior to 18.1R3-S8 on EX4300; 18.2 versions prior to 18.2R3-S2 on EX4300; 18.3 versions prior to 18.3R2-S3, 18.3R3, 18.3R3-S1 on EX4300; 18.4 versions prior to 18.4R1-S5, 18.4R2-S3, 18.4R3 on EX4300; 19.1 versions prior to 19.1R1-S4, 19.1R2 on EX4300; 19.2 versions prior to 19.2R1-S4, 19.2R2 on EX4300; 19.3 versions prior to 19.3R1-S1, 19.3R2 on EX4300.
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Analysis
by VulDB Data Team • 05/17/2024
The vulnerability described in CVE-2020-1628 represents a critical information exposure issue within Juniper Networks Junos OS operating on EX4300 switch devices. This flaw stems from the improper handling of internal network communications that utilize the 128.0.0.0/2 subnet, a private address range typically reserved for internal network operations. The configuration of these switches inadvertently allows packets containing sensitive operational data to escape the internal network boundary, creating an unintended information disclosure channel that could be exploited by external adversaries.
The technical root cause of this vulnerability lies in the network switch's packet forwarding behavior when processing traffic within the designated internal subnet. The 128.0.0.0/2 network range, while not globally routable, contains specific IP addresses that are used by the Routing Engine (RE) and Packet Forwarding Engine (PFE) for internal heartbeat communications and system status updates. When these internal packets are not properly filtered or restricted, they can traverse the switch's external interfaces and reach external networks, potentially exposing critical system information such as kernel versions, heartbeat signals, and other configuration metadata that would normally remain within the device's internal network infrastructure.
This information exposure vulnerability significantly impacts network security posture by providing attackers with valuable intelligence about the target network infrastructure. The leaked information includes kernel versions, which can reveal the specific Junos OS version and potentially indicate known vulnerabilities or exploits that may be applicable to the target devices. Heartbeat communications provide insight into the operational status and timing of network components, while other configuration data can help attackers understand network topology and device configurations. This type of information leakage directly aligns with attack patterns described in the MITRE ATT&CK framework under the information gathering phase, where adversaries collect network information to plan subsequent attacks.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential entry point for more sophisticated attacks. Network defenders who are unaware of this information leakage may inadvertently allow attackers to use the exposed data for reconnaissance purposes, potentially leading to privilege escalation or other advanced persistent threats. The vulnerability affects multiple Junos OS versions across different release branches, indicating a widespread issue that requires immediate attention from network administrators and security teams managing Juniper EX4300 switches. Organizations with exposed devices may find their network infrastructure more susceptible to targeted attacks, as attackers can use the leaked information to tailor their exploitation strategies.
The recommended mitigation strategy involves applying the appropriate software patches provided by Juniper Networks for each affected version and release branch. Security teams should prioritize patching devices running vulnerable Junos OS versions, particularly those in production environments where network exposure is high. Network segmentation and firewall rules should be implemented to prevent external access to internal network ranges, though this approach may be insufficient if the vulnerability allows packets to escape through legitimate network paths. Additionally, network administrators should consider implementing monitoring solutions to detect unusual traffic patterns that might indicate information leakage from internal network communications, as this vulnerability represents a sophisticated attack vector that may not be immediately apparent through standard network monitoring procedures. The vulnerability classification aligns with CWE-200, which addresses information exposure, and represents a significant concern for organizations maintaining network security compliance and operational resilience standards.