CVE-2014-3817 in Junos
Summary
by MITRE
Juniper Junos 11.4 before 11.4R12, 12.1X44 before 12.1X44-D32, 12.1X45 before 12.1X45-D25, 12.1X46 before 12.1X46-D20, and 12.1X47 before 12.1X47-D10 on SRX Series devices, when NAT protocol translation from IPv4 to IPv6 is enabled, allows remote attackers to cause a denial of service (flowd hang or crash) via a crafted packet.
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Analysis
by VulDB Data Team • 02/08/2022
The vulnerability identified as CVE-2014-3817 affects Juniper Junos operating system versions running on SRX Series devices, specifically targeting configurations where Network Address Translation (NAT) protocol translation from IPv4 to IPv6 is enabled. This issue represents a critical denial of service weakness that can be exploited by remote attackers to disrupt network services. The affected versions include multiple release branches of Junos software, with specific patch levels required to address the vulnerability. The flaw manifests when the system processes crafted packets that trigger abnormal behavior in the flowd daemon responsible for managing network flow information.
The technical root cause of this vulnerability lies in the improper handling of packets during IPv4 to IPv6 NAT protocol translation processes. When the system encounters specially crafted packets that conform to specific patterns within the translation framework, the flowd process becomes unresponsive or crashes entirely. This occurs due to insufficient input validation and error handling within the NAT implementation, particularly when processing packets that contain malformed or unexpected data structures. The vulnerability specifically impacts the flowd daemon which is responsible for maintaining flow tracking information and managing network traffic flow statistics. The flaw demonstrates characteristics consistent with CWE-121, heap-based buffer overflow, and CWE-122, stack-based buffer overflow, as the system fails to properly validate packet contents before processing them through the NAT translation pipeline.
The operational impact of this vulnerability is severe and can result in complete service disruption for affected SRX Series devices. When the flowd daemon hangs or crashes, the device loses its ability to properly track network flows, leading to potential network outages and loss of visibility into traffic patterns. Network administrators may experience complete denial of service conditions where the device becomes unresponsive to management traffic, and network connectivity is severely impacted. The vulnerability affects the availability aspect of the CIA triad by compromising the system's ability to maintain continuous operation. Attackers can exploit this weakness without requiring authentication credentials, making it particularly dangerous as it allows for remote exploitation from any location on the network. The impact extends beyond immediate service disruption to include potential data loss, logging gaps, and complete network management paralysis.
Mitigation strategies for CVE-2014-3817 involve immediate implementation of software patches provided by Juniper, specifically updating to the patched versions mentioned in the advisory. Organizations should also implement network segmentation to isolate SRX devices and limit potential attack surfaces. Configuration changes can include disabling IPv4 to IPv6 NAT protocol translation when not required, which eliminates the attack vector entirely. Network monitoring should be enhanced to detect anomalous flowd behavior and potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1499.004, "Endpoint Denial of Service," and represents a classic example of how improper input validation can lead to system instability. Security teams should also consider implementing intrusion detection systems that can identify and alert on suspicious packet patterns that may indicate exploitation attempts. Regular vulnerability assessments and network audits should be conducted to identify other potential weaknesses in the Junos configuration that could be exploited in similar fashion.