CVE-2019-0010 in Junos
Summary
by MITRE
An SRX Series Service Gateway configured for Unified Threat Management (UTM) may experience a system crash with the error message "mbuf exceed" -- an indication of memory buffer exhaustion -- due to the receipt of crafted HTTP traffic. Each crafted HTTP packet inspected by UTM consumes mbufs which can be identified through the following log messages: all_logs.0:Jun 8 03:25:03 srx1 node0.fpc4 : SPU3 jmpi mbuf stall 50%. all_logs.0:Jun 8 03:25:13 srx1 node0.fpc4 : SPU3 jmpi mbuf stall 51%. all_logs.0:Jun 8 03:25:24 srx1 node0.fpc4 : SPU3 jmpi mbuf stall 52%. ... Eventually the system runs out of mbufs and the system crashes (fails over) with the error "mbuf exceed". This issue only occurs when HTTP AV inspection is configured. Devices configured for Web Filtering alone are unaffected by this issue. Affected releases are Junos OS on SRX Series: 12.1X46 versions prior to 12.1X46-D81; 12.3X48 versions prior to 12.3X48-D77; 15.1X49 versions prior to 15.1X49-D101, 15.1X49-D110.
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Analysis
by VulDB Data Team • 07/01/2023
This vulnerability affects Palo Alto Networks SRX Series Service Gateways operating in Unified Threat Management mode, specifically targeting the memory management system during HTTP traffic inspection. The flaw manifests as a memory buffer exhaustion condition triggered by specially crafted HTTP packets that are processed through the antivirus inspection engine. The system crash occurs when the mbuf (memory buffer) pool becomes depleted, causing the device to fail over and become unavailable. This represents a denial of service condition that can disrupt network operations and compromise security infrastructure availability.
The technical implementation of this vulnerability stems from insufficient memory management within the UTM inspection process. When HTTP traffic is inspected for antivirus threats, each packet consumes mbuf resources that are not properly reclaimed or managed during the inspection cycle. The logging messages indicate a progressive mbuf exhaustion pattern where the system reports increasing stall percentages, demonstrating the gradual depletion of available memory buffers. This memory leak occurs specifically within the SPU3 (Security Processing Unit) component and is tied to the jmpi (Juniper Memory Management Interface) subsystem. The vulnerability is classified under CWE-400 as an Uncontrolled Resource Consumption vulnerability, representing a classic resource exhaustion attack vector.
The operational impact of this vulnerability extends beyond simple service disruption to compromise the overall security posture of networks relying on SRX Series gateways for threat protection. Organizations using these devices in UTM mode face potential security gaps when the system crashes, leaving network traffic unmonitored and vulnerable to threats. The failure mode results in automatic failover which may not be immediately detected, potentially creating blind spots in network security monitoring. This vulnerability directly impacts the availability component of the CIA triad and can be leveraged by attackers to perform denial of service attacks against critical network infrastructure. According to ATT&CK framework, this maps to technique T1499.004 (Evasion: File System Wipe) and T1498 (Network Denial of Service) through the disruption of network security services.
Mitigation strategies should focus on immediate patch application for affected Junos OS versions, with specific attention to the release versions mentioned in the advisory. Network administrators should consider disabling HTTP antivirus inspection if the functionality is not critical to their security requirements, though this reduces threat detection capabilities. Monitoring for the specific log messages indicating mbuf stall conditions provides early warning of potential exploitation attempts. The recommended approach involves implementing rate limiting on HTTP traffic to prevent rapid consumption of memory buffers, along with regular system health monitoring to detect memory exhaustion patterns before complete system failure occurs. Network segmentation and redundant security appliances can help maintain operational continuity during patch deployment. Organizations should also review their incident response procedures to ensure rapid detection and recovery from such memory exhaustion events.