CVE-2017-2304 in Junos
Summary
by MITRE
Juniper Networks QFX3500, QFX3600, QFX5100, QFX5200, EX4300 and EX4600 devices running Junos OS 14.1X53 prior to 14.1X53-D40, 15.1X53 prior to 15.1X53-D40, 15.1 prior to 15.1R2, do not pad Ethernet packets with zeros, and thus some packets can contain fragments of system memory or data from previous packets. This issue is also known as 'Etherleak'
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/26/2020
The vulnerability identified as CVE-2017-2304 affects Juniper Networks network infrastructure devices including QFX3500, QFX3600, QFX5100, QFX5200, EX4300, and EX4600 platforms running specific versions of Junos OS. This security flaw represents a critical information disclosure vulnerability that stems from improper Ethernet packet handling within the network operating system. The issue is commonly referred to as "Etherleak" due to its mechanism of exposing unintended data fragments from system memory or previous packets within network traffic. The vulnerability manifests when the affected devices fail to properly pad Ethernet frames with zeros, creating a scenario where packet boundaries become inconsistent with expected network protocols.
The technical implementation of this vulnerability involves the network device's failure to maintain proper packet padding standards during frame construction. When packets are processed through the network interface, the absence of zero padding means that the Ethernet frame structure does not conform to standard expectations. This creates opportunities for data leakage where fragments of system memory or remnants from previously processed packets can become embedded within the current packet payload. The flaw specifically impacts devices running Junos OS versions prior to the mentioned patch levels, where the packet processing logic does not adequately sanitize or pad outgoing frames to prevent memory leakage. This issue is classified under CWE-200 as "Information Exposure" and represents a direct violation of data confidentiality principles in network communications.
The operational impact of CVE-2017-2304 extends beyond simple information disclosure, as it can potentially expose sensitive data including cryptographic keys, session tokens, user credentials, or other confidential information that may reside in memory buffers. Attackers who can intercept network traffic between affected devices may be able to reconstruct fragments of system memory or previous packet contents, potentially leading to credential theft, session hijacking, or other advanced persistent threats. The vulnerability is particularly concerning in environments where these devices serve as core network infrastructure components, as the exposure of memory fragments could provide attackers with sufficient information to launch more sophisticated attacks. This aligns with ATT&CK technique T1005 for "Data from Local System" and T1041 for "Exfiltration Over C2 Channel" when exploited in targeted attack scenarios.
Mitigation strategies for this vulnerability require immediate deployment of the applicable Juniper security patches and firmware updates for the affected device models and software versions. Network administrators should prioritize patching all affected devices in their environment, particularly those handling sensitive traffic or serving as network core components. Additionally, implementing network segmentation and monitoring solutions can help detect anomalous packet patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper memory management and packet padding in network operating systems, highlighting the need for comprehensive security testing of low-level network protocols. Organizations should also consider implementing network traffic analysis tools to monitor for unusual packet structures that could indicate the presence of this vulnerability in unpatched systems. Regular security assessments of network infrastructure components are essential to identify and remediate similar vulnerabilities that could compromise network confidentiality and integrity.