CVE-2019-0052 in Junos
Summary
by MITRE
The srxpfe process may crash on SRX Series services gateways when the UTM module processes a specific fragmented HTTP packet. The packet is misinterpreted as a regular TCP packet which causes the processor to crash. This issue affects all SRX Series platforms that support URL-Filtering and have web-filtering enabled. Affected releases are Juniper Networks Junos OS: 12.3X48 versions prior to 12.3X48-D85 on SRX Series; 15.1X49 versions prior to 15.1X49-D181, 15.1X49-D190 on SRX Series; 17.3 versions on SRX Series; 17.4 versions prior to 17.4R1-S8, 17.4R2-S5, 17.4R3 on SRX Series; 18.1 versions prior to 18.1R3-S6 on SRX Series; 18.2 versions prior to 18.2R2-S1, 18.2R3 on SRX Series; 18.3 versions prior to 18.3R1-S2, 18.3R2 on SRX Series; 18.4 versions prior to 18.4R1-S1, 18.4R2 on SRX Series.
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Analysis
by VulDB Data Team • 10/24/2023
The vulnerability described in CVE-2019-0052 represents a critical denial-of-service flaw within Juniper Networks SRX Series services gateways that specifically targets the srxpfe process responsible for packet forwarding and security processing. This issue arises from a fundamental misinterpretation within the Unified Threat Management (UTM) module where fragmented HTTP packets are incorrectly classified as regular TCP packets, leading to a complete system crash. The flaw demonstrates a classic buffer over-read or parsing error where the packet processing engine fails to properly validate the packet structure before attempting to process it, resulting in an unhandled exception that terminates the srxpfe process. The vulnerability affects a broad range of Junos OS versions across multiple release lines, indicating this was a widespread issue that required coordinated patching across different platform generations.
The technical execution of this vulnerability occurs when the UTM module receives a specially crafted fragmented HTTP packet that exploits a parsing inconsistency in how the system handles packet fragmentation. When the srxpfe process encounters such a packet, it incorrectly interprets the fragment headers and payload structure, causing the processor to follow an execution path that leads to memory corruption or invalid memory access. This misinterpretation creates a condition where the system's packet processing logic fails to properly account for the fragmented nature of the packet, treating it as a continuous TCP stream instead of properly handling the fragmentation boundaries. The vulnerability operates at the network packet processing layer, specifically affecting the UTM module's ability to correctly parse and classify packets for web-filtering and URL-filtering operations. This type of flaw is categorized under CWE-129 Input Validation and CWE-787 Out-of-bounds Write, representing both validation and memory corruption vulnerabilities that can lead to system instability.
The operational impact of CVE-2019-0052 extends beyond simple service disruption as it can result in complete gateway failure, leaving network traffic unfiltered and potentially exposing the network to security threats during the outage period. Organizations relying on SRX Series gateways for web filtering and content control would experience immediate loss of security services, creating a window where malicious web traffic could bypass traditional filtering mechanisms. The vulnerability's exploitation requires minimal network activity, making it particularly dangerous as it could be triggered by automated attacks or simply by normal network traffic containing malformed packets. This issue affects all SRX Series platforms that support URL-filtering functionality, making it a significant concern for enterprises that depend on Juniper's security appliances for their network protection infrastructure. The widespread nature of affected releases means that organizations across multiple Junos OS versions would need to implement immediate patching strategies to maintain their security posture.
Mitigation strategies for CVE-2019-0052 involve immediate deployment of the vendor-supplied patches and firmware updates that address the packet parsing logic within the srxpfe process. Network administrators should prioritize patching all affected SRX Series platforms, particularly those with web-filtering and URL-filtering enabled, as these configurations are most vulnerable to exploitation. The patching process should include thorough testing in non-production environments to ensure compatibility with existing network configurations and security policies. Organizations should also implement network monitoring to detect unusual traffic patterns that might indicate exploitation attempts, though the vulnerability is likely to be triggered by legitimate network traffic rather than malicious activity. Configuration management should include disabling web-filtering functionality on affected systems until patches are deployed, though this creates a security gap that must be carefully managed. The vulnerability's impact aligns with ATT&CK technique T1499.004, which covers network disruption through denial-of-service attacks, and organizations should consider implementing additional network segmentation and redundancy measures to minimize the impact of such vulnerabilities on critical network services.