CVE-2015-0887 in SEIL
Summary
by MITRE
npppd in the PPP Access Concentrator (PPPAC) on SEIL SEIL/x86 Fuji routers 1.00 through 3.30, SEIL/X1 routers 3.50 through 4.70, SEIL/X2 routers 3.50 through 4.70, and SEIL/B1 routers 3.50 through 4.70 allows remote attackers to cause a denial of service (infinite loop and device hang) via a crafted SSTP packet.
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Analysis
by VulDB Data Team • 04/14/2018
The vulnerability identified as CVE-2015-0887 resides within the Network Policy and Protocols PPP daemon (npppd) component of SEIL routers, specifically affecting multiple router models including Fuji, X1, X2, and B1 series. This issue manifests as a remote denial of service condition that can be triggered through manipulation of Secure Socket Tunneling Protocol (SSTP) packets, representing a significant security weakness in network infrastructure devices that handle remote access connections. The affected software versions span from 1.00 through 3.30 for Fuji routers and 3.50 through 4.70 for the other router series, indicating a widespread exposure across multiple product generations.
The technical flaw stems from inadequate input validation within the npppd implementation when processing SSTP packets, which are typically used for secure remote access connections over SSL/TLS. When a specially crafted SSTP packet is received by the vulnerable router, the processing logic enters an infinite loop that consumes excessive CPU resources and ultimately causes the device to hang or become unresponsive. This condition represents a classic buffer overflow or input validation vulnerability that falls under the CWE-121 category of buffer overflow conditions, where insufficient validation of incoming data leads to unpredictable system behavior. The vulnerability operates at the network protocol level, making it particularly dangerous as it can be exploited without requiring authentication or local access to the device.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network availability and business continuity for organizations relying on these routers for remote access services. Network administrators who depend on these devices for PPP connections may experience complete service outages when attackers exploit this weakness, as the device becomes unresponsive and requires manual intervention to restore functionality. The infinite loop condition can persist until the device is manually rebooted or the network connection is terminated, creating extended downtime periods that can be particularly damaging in mission-critical environments. This vulnerability also aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries target network infrastructure to disrupt services and create operational chaos.
Organizations should implement immediate mitigations including firmware updates from SEIL to address the vulnerability, network segmentation to isolate affected devices, and monitoring for suspicious SSTP traffic patterns that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of input validation in network protocol implementations and highlights the need for robust security testing of network infrastructure components. Additional defensive measures include implementing intrusion detection systems that can identify anomalous SSTP packet patterns and establishing automated alerting for device performance degradation that might indicate exploitation. Network administrators should also consider disabling SSTP functionality on affected devices until patches are applied, as this represents a fundamental security weakness that can be exploited remotely without authentication credentials. The vulnerability serves as a reminder of the critical security considerations that must be addressed in embedded network devices where resource constraints often lead to insufficient input validation mechanisms.