CVE-2015-7749 in Junos
Summary
by MITRE
The PFE daemon in Juniper vSRX virtual firewalls with Junos OS before 15.1X49-D20 allows remote attackers to cause a denial of service via an unspecified connection request to the "host-OS."
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Analysis
by VulDB Data Team • 06/22/2022
The vulnerability identified as CVE-2015-7749 affects the PFE daemon within Juniper vSRX virtual firewalls running Junos OS versions prior to 15.1X49-D20. This issue represents a significant denial of service weakness that can be exploited by remote attackers to disrupt network security operations. The vulnerability specifically targets the host-OS connection mechanism, which serves as a critical interface for communication between the packet forwarding engine and the host operating system. The PFE daemon operates within the data plane of the firewall and is responsible for processing network traffic at high speeds, making it a crucial component for maintaining network security and performance.
The technical flaw manifests when an attacker sends an unspecified connection request to the host-OS interface of the PFE daemon. This particular attack vector demonstrates a lack of proper input validation and error handling within the daemon's connection processing logic. The vulnerability falls under the category of improper input validation as defined by CWE-20, where the system fails to adequately validate connection requests before processing them. The flaw essentially allows an attacker to send malformed or specially crafted connection requests that cause the PFE daemon to crash or become unresponsive, leading to a complete denial of service condition that affects the entire firewall appliance.
The operational impact of this vulnerability extends beyond simple service disruption, as it directly affects the network security infrastructure that organizations rely upon for protection. When the PFE daemon becomes unavailable, the vSRX firewall loses its ability to process network packets effectively, potentially allowing malicious traffic to bypass security controls or causing legitimate traffic to be dropped. This vulnerability particularly affects organizations using older Junos OS versions, creating a window of exposure where network security can be compromised through relatively simple remote attacks. The attack requires no authentication and can be executed from outside the network, making it especially dangerous for organizations that do not properly segment their network infrastructure or implement adequate monitoring solutions.
Organizations should immediately apply the security patch released by Juniper for version 15.1X49-D20 and subsequent releases to remediate this vulnerability. The mitigation strategy should also include implementing network segmentation to limit access to the PFE daemon interfaces and deploying monitoring solutions that can detect unusual connection patterns or daemon behavior that might indicate exploitation attempts. From an attacker perspective, this vulnerability aligns with techniques described in the ATT&CK framework under the T1499 category for network denial of service, where adversaries target network infrastructure to disrupt operations. The vulnerability also relates to T1071 which covers application layer protocol usage, as the attack leverages specific protocol implementations within the firewall's communication stack. Network administrators should also consider implementing intrusion detection systems that can identify and alert on suspicious connection attempts to host-OS interfaces, providing an additional layer of defense against such attacks.