CVE-2014-7256 in SEIL Plus
Summary
by MITRE
The (1) PPP Access Concentrator (PPPAC) and (2) Dial-Up Networking Internet Initiative Japan Inc. SEIL series routers SEIL/x86 Fuji 1.00 through 3.22; SEIL/X1, SEIL/X2, and SEIL/B1 1.00 through 4.62; SEIL/Turbo 1.82 through 2.18; and SEIL/neu 2FE Plus 1.82 through 2.18 allow remote attackers to cause a denial of service (restart) via crafted (a) GRE or (b) MPPE packets.
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Analysis
by VulDB Data Team • 04/09/2018
The vulnerability identified as CVE-2014-7256 affects multiple router models manufactured by Dial-Up Networking Internet Initiative Japan Inc. including the SEIL series routers across various product lines such as SEIL/x86 Fuji, SEIL/X1, SEIL/X2, SEIL/B1, SEIL/Turbo, and SEIL/neu 2FE Plus. These devices operate with firmware versions ranging from 1.00 through 3.22 for some models and 1.00 through 4.62 for others, creating a widespread exposure across different hardware platforms. The vulnerability specifically targets the PPP Access Concentrator functionality and Dial-Up Networking capabilities within these router implementations.
The technical flaw manifests through improper handling of crafted network packets, particularly GRE (Generic Routing Encapsulation) and MPPE (Microsoft Point-to-Point Encryption) packets. When these specially crafted packets are transmitted to the affected routers, the devices fail to properly validate or process the packet structures, leading to a system restart or denial of service condition. This represents a classic buffer overflow or input validation vulnerability where the router's packet processing logic does not adequately sanitize incoming network traffic, allowing maliciously constructed packets to trigger unexpected behavior in the routing software.
The operational impact of this vulnerability is significant as it enables remote attackers to perform denial of service attacks against network infrastructure without requiring any authentication credentials or physical access to the devices. The affected routers could be restarted remotely, potentially disrupting network connectivity for users relying on these connections. This vulnerability particularly affects enterprise and residential networks that depend on these specific router models for internet connectivity, as attackers could repeatedly exploit the flaw to maintain persistent disruption of services. The restart condition effectively renders the affected network devices temporarily unavailable, causing service interruptions that could range from minor inconveniences to major network outages depending on the criticality of the affected infrastructure.
Mitigation strategies for CVE-2014-7256 should prioritize firmware updates from the vendor to address the packet processing flaws in the affected router models. Network administrators should implement firewall rules to filter or drop suspicious GRE and MPPE packets at network boundaries, particularly when these protocols are not required for legitimate network operations. Additionally, network segmentation and monitoring should be employed to detect unusual restart patterns or packet traffic that might indicate exploitation attempts. The vulnerability aligns with CWE-129, which addresses improper validation of input ranges, and represents a typical ATT&CK technique under T1499.004 for network denial of service attacks. Organizations should also consider implementing intrusion detection systems to monitor for patterns consistent with this vulnerability and establish incident response procedures to quickly address exploitation attempts. Regular security assessments and network audits should be conducted to identify and remediate similar vulnerabilities in other network infrastructure components.