CVE-2018-0154 in IOS
Summary
by MITRE
A vulnerability in the crypto engine of the Cisco Integrated Services Module for VPN (ISM-VPN) running Cisco IOS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient handling of VPN traffic by the affected device. An attacker could exploit this vulnerability by sending crafted VPN traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to hang or crash, resulting in a DoS condition. Cisco Bug IDs: CSCvd39267.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2018-0154 resides within the cryptographic engine of Cisco's Integrated Services Module for VPN (ISM-VPN) running Cisco IOS Software, representing a critical security weakness that undermines the integrity of network infrastructure. This flaw specifically targets the processing capabilities of VPN traffic within the affected hardware modules, creating an exploitable condition that can be leveraged by unauthorized remote actors without requiring authentication credentials. The vulnerability manifests through inadequate validation and handling mechanisms within the cryptographic processing pipeline, where the system fails to properly manage certain types of VPN traffic patterns that could overwhelm or corrupt the processing units responsible for encryption and decryption operations.
The technical exploitation of this vulnerability occurs through the transmission of specifically crafted VPN traffic packets designed to trigger the flawed cryptographic handling routines within the ISM-VPN module. When the affected device receives these maliciously constructed packets, the insufficient input validation and error handling mechanisms cause the system to enter an unstable state where normal processing functions become compromised. The exploitation process typically involves sending traffic that either exceeds the expected processing parameters or contains malformed cryptographic elements that the device cannot properly interpret or discard. This leads to a cascading failure where the cryptographic engine becomes unresponsive or enters a state where it can no longer maintain its operational integrity, ultimately resulting in the complete or partial system failure that constitutes the denial of service condition.
The operational impact of CVE-2018-0154 extends beyond simple service interruption to potentially compromise the entire network security posture of organizations relying on Cisco ISM-VPN modules. When an affected device crashes or becomes unresponsive, it creates network outages that can disrupt critical business operations, particularly in environments where VPN connectivity is essential for remote access, branch office connectivity, or secure communications. The vulnerability affects the availability aspect of the CIA triad by making network resources inaccessible to legitimate users, while simultaneously creating potential attack vectors that could be combined with other exploits to achieve more sophisticated compromise objectives. Organizations utilizing this hardware platform face significant risk of operational disruption, increased administrative overhead for system recovery, and potential exposure of sensitive data if the DoS condition prevents proper logging or monitoring functions from operating correctly.
Mitigation strategies for CVE-2018-0154 should focus on immediate defensive measures including applying the relevant Cisco IOS software patches that address the cryptographic handling deficiencies, implementing network segmentation to isolate affected devices, and establishing monitoring protocols to detect unusual VPN traffic patterns that might indicate exploitation attempts. Organizations should also consider implementing rate limiting mechanisms on VPN traffic to prevent the exploitation of the vulnerability through excessive packet flooding, while maintaining detailed logging of cryptographic operations to identify potential attack signatures. The vulnerability aligns with CWE-20, which describes improper input validation, and falls under ATT&CK technique T1499.004 for network denial of service, making it a significant concern for cybersecurity teams implementing comprehensive threat detection and response capabilities. Cisco's advisory CSCvd39267 provides specific guidance for affected configurations and recommended remediation steps that should be implemented immediately to protect against exploitation attempts targeting this cryptographic weakness.