CVE-2018-0002 in Junos SRX
Summary
by MITRE
On SRX Series and MX Series devices with a Service PIC with any ALG enabled, a crafted TCP/IP response packet processed through the device results in memory corruption leading to a flowd daemon crash. Sustained crafted response packets lead to repeated crashes of the flowd daemon which results in an extended Denial of Service condition. Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D60 on SRX series; 12.3X48 versions prior to 12.3X48-D35 on SRX series; 14.1 versions prior to 14.1R9 on MX series; 14.2 versions prior to 14.2R8 on MX series; 15.1X49 versions prior to 15.1X49-D60 on SRX series; 15.1 versions prior to 15.1R5-S8, 15.1F6-S9, 15.1R6-S4, 15.1R7 on MX series; 16.1 versions prior to 16.1R6 on MX series; 16.2 versions prior to 16.2R3 on MX series; 17.1 versions prior to 17.1R2-S4, 17.1R3 on MX series. No other Juniper Networks products or platforms are affected by this issue.
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Analysis
by VulDB Data Team • 01/20/2023
This vulnerability affects Juniper Networks SRX Series and MX Series devices that utilize Service PICs with Application Layer Gateway (ALG) functionality enabled. The flaw manifests when processing crafted TCP/IP response packets that traverse the device, resulting in memory corruption within the flowd daemon. The flowd daemon is responsible for flow logging and statistics collection in Junos OS environments, making this vulnerability particularly concerning for network monitoring and security operations. The issue stems from insufficient input validation and memory management within the ALG processing pipeline, where maliciously constructed packets can trigger buffer overflows or other memory corruption conditions that ultimately lead to daemon termination.
The technical exploitation of this vulnerability requires sending specifically crafted TCP/IP response packets to devices with ALG enabled, particularly those configured with SIP ALG or other application layer protocols. When these packets are processed through the Service PIC's ALG functionality, the memory corruption occurs in the flowd daemon's memory management routines, causing the daemon to crash. The vulnerability is classified as a memory corruption issue that can be categorized under CWE-121 as heap-based buffer overflow or similar memory safety violations. The attack vector is network-based and requires no authentication, making it particularly dangerous as it can be exploited remotely by attackers who can send packets to the affected devices.
The operational impact of this vulnerability extends beyond simple daemon crashes to create sustained denial of service conditions. Repeated exploitation with crafted packets can cause continuous flowd daemon restarts, leading to extended periods where network flow logging becomes unavailable. This impacts security monitoring capabilities, network visibility, and operational integrity of the affected infrastructure. The flowd daemon crash results in loss of flow statistics, which are critical for network troubleshooting, security analysis, and compliance reporting. Organizations relying on Juniper devices for network security and monitoring may experience significant operational disruption when this vulnerability is exploited, potentially masking other security incidents or preventing proper network analysis during incident response activities.
Mitigation strategies should focus on immediate patch application to affected Junos OS versions, as recommended by Juniper's security advisories. Network administrators should also implement network segmentation and access controls to limit exposure of affected devices to untrusted networks. Monitoring for unusual flowd daemon restart patterns and implementing intrusion detection systems that can identify crafted TCP/IP packets targeting this vulnerability can provide additional defense layers. Organizations should consider disabling ALG functionality on devices where it is not strictly required, particularly for services that do not rely on application layer protocol inspection. The vulnerability demonstrates the importance of proper input validation and memory safety practices in network security devices, aligning with ATT&CK technique T1499.002 for network disruption and T1566 for credential harvesting through network-based attacks. Regular security assessments and vulnerability scanning should be implemented to identify and remediate similar issues in other network infrastructure components.