CVE-2017-10608 in Junos
Summary
by MITRE
Any Juniper Networks SRX series device with one or more ALGs enabled may experience a flowd crash when traffic is processed by the Sun/MS-RPC ALGs. This vulnerability in the Sun/MS-RPC ALG services component of Junos OS allows an attacker to cause a repeated denial of service against the target. Repeated traffic in a cluster may cause repeated flip-flop failure operations or full failure to the flowd daemon halting traffic on all nodes. Only IPv6 traffic is affected by this issue. IPv4 traffic is unaffected. This issues is not seen with to-host traffic. This issue has no relation with HA services themselves, only the ALG service. No other Juniper Networks products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS 12.1X46 prior to 12.1X46-D55 on SRX; 12.1X47 prior to 12.1X47-D45 on SRX; 12.3X48 prior to 12.3X48-D32, 12.3X48-D35 on SRX; 15.1X49 prior to 15.1X49-D60 on SRX.
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Analysis
by VulDB Data Team • 01/16/2021
The vulnerability identified as CVE-2017-10608 represents a critical denial of service weakness within Juniper Networks SRX series firewalls, specifically affecting the Application Layer Gateway (ALG) services component. This flaw manifests when the Sun/MS-RPC ALG services process IPv6 traffic, leading to destabilization of the flowd daemon which manages flow tracking and forwarding operations. The vulnerability operates through a flaw in how the ALG service handles certain network protocols, creating a condition where repeated processing of affected traffic triggers system instability. The issue is particularly concerning because it can cause cascading failures across clustered environments where multiple nodes depend on the flowd daemon for proper traffic management. The technical implementation involves a memory management error or buffer handling issue within the ALG service that becomes apparent under sustained load conditions with specific IPv6 traffic patterns.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromising network availability and stability. When the flowd daemon crashes repeatedly due to processing Sun/MS-RPC ALG traffic, the entire network infrastructure managed by the affected SRX devices experiences significant degradation. In clustered deployments, the repeated flip-flop failure operations can lead to complete service outages across all nodes in the cluster, as the flowd daemon is essential for maintaining network flow state information. The vulnerability affects only IPv6 traffic processing through the ALG services, making it more specific but still potentially devastating in environments where IPv6 is actively utilized. The fact that IPv4 traffic remains unaffected provides some operational clarity for network administrators, though it does not mitigate the overall risk in mixed protocol environments where IPv6 traffic may be processed through ALG services. This vulnerability directly relates to CWE-121, which addresses stack-based buffer overflow conditions, and may also involve CWE-125, heap-based buffer overflows, depending on the specific implementation details.
The attack surface for this vulnerability is limited to Juniper SRX series devices running affected versions of Junos OS with ALG services enabled, specifically targeting the Sun/MS-RPC ALG functionality. The ATT&CK framework categorizes this vulnerability under T1499.004, which involves network denial of service attacks through manipulation of network infrastructure. Attackers can exploit this weakness by sending specifically crafted IPv6 traffic that triggers the ALG service to process Sun/MS-RPC protocols, causing repeated daemon crashes. The exploitation requires minimal privileges and can be executed from external network positions, making it particularly dangerous in perimeter security contexts. The vulnerability does not affect HA services directly but rather the ALG processing layer that operates independently of the high availability mechanisms. Network administrators must consider this vulnerability in their threat modeling for SRX devices, particularly those managing IPv6 traffic flows that utilize ALG services. The affected release versions span multiple Junos OS branches, indicating a widespread exposure across different product lines and suggesting that organizations may have been vulnerable across multiple years of deployments.
Mitigation strategies for CVE-2017-10608 should prioritize immediate patch deployment to affected Junos OS versions, with specific attention to the release branches mentioned in the vulnerability description. Organizations should disable ALG services for Sun/MS-RPC protocols if they are not actively required, as this provides a direct workaround to prevent exploitation. Network segmentation and traffic filtering can help limit the impact by preventing the specific IPv6 traffic patterns that trigger the vulnerability. Monitoring for flowd daemon stability and implementing automated alerting for repeated daemon restarts can provide early detection of attempted exploitation. The patching strategy should include comprehensive testing in non-production environments before deployment to ensure compatibility with existing network configurations. Additionally, network administrators should consider implementing traffic analysis tools to identify and potentially block IPv6 traffic patterns that may trigger the ALG service processing. The vulnerability demonstrates the importance of maintaining current security patches and the potential risks associated with enabling unnecessary services such as ALGs, which can create attack vectors even when not actively used in the network architecture.