CVE-2018-0101 in ASA
Summary
by MITRE
A vulnerability in the Secure Sockets Layer (SSL) VPN functionality of the Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause a reload of the affected system or to remotely execute code. The vulnerability is due to an attempt to double free a region of memory when the webvpn feature is enabled on the Cisco ASA device. An attacker could exploit this vulnerability by sending multiple, crafted XML packets to a webvpn-configured interface on the affected system. An exploit could allow the attacker to execute arbitrary code and obtain full control of the system, or cause a reload of the affected device. This vulnerability affects Cisco ASA Software that is running on the following Cisco products: 3000 Series Industrial Security Appliance (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, ASA 1000V Cloud Firewall, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4110 Security Appliance, Firepower 9300 ASA Security Module, Firepower Threat Defense Software (FTD). Cisco Bug IDs: CSCvg35618.
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Analysis
by VulDB Data Team • 07/20/2024
The vulnerability identified as CVE-2018-0101 represents a critical memory corruption issue within Cisco Adaptive Security Appliance (ASA) software that fundamentally compromises system integrity and availability. This flaw exists within the Secure Sockets Layer (SSL) VPN functionality of the affected devices, creating a pathway for unauthenticated remote attackers to gain complete control over the targeted systems. The vulnerability stems from improper memory management practices where the system attempts to free the same memory region twice, a classic double free error that can lead to unpredictable behavior and system exploitation. The issue specifically manifests when the webvpn feature is enabled on Cisco ASA devices, making it particularly dangerous as it affects a core security function that many organizations rely upon for remote access and network protection.
The technical exploitation of this vulnerability requires an attacker to send multiple specially crafted XML packets to an interface configured with webvpn functionality. This attack vector aligns with common remote code execution techniques found in software vulnerabilities and demonstrates how malformed input processing can lead to system compromise. The double free condition occurs during the processing of these XML packets, where the memory management subsystem attempts to release memory that has already been freed, potentially creating a scenario where attacker-controlled data can be used to manipulate the memory layout and execute arbitrary code. This type of vulnerability is classified under CWE-415 as Double Free, which is a well-documented memory safety issue that has been exploited in numerous security incidents across various platforms. The attack can result in either remote code execution with full system privileges or a denial of service condition causing a device reload, effectively providing attackers with both persistent access and availability disruption capabilities.
The operational impact of CVE-2018-0101 extends across multiple Cisco product lines, affecting a broad range of security appliances that organizations depend upon for network protection. The affected devices include the 3000 Series Industrial Security Appliance (ISA), various ASA 5500 Series appliances, ASA 5500-X Next-Generation Firewalls, and multiple Firepower series devices, indicating the widespread nature of this vulnerability. This breadth of impact means that organizations with diverse security infrastructures could simultaneously face exposure to the same vulnerability, creating cascading security risks across multiple network segments. The vulnerability's potential for remote code execution places it firmly within the ATT&CK framework's T1059.007 technique category, specifically targeting remote access services and network infrastructure components. The ability to cause device reloads also maps to T1490 (Inhibit System Recovery) and T1566 (Phishing) attack patterns, as organizations may inadvertently expose their systems to exploitation through routine network traffic processing.
Organizations must implement immediate mitigations to address this vulnerability, including applying Cisco's security patches and updates as released through their official advisory channels. Network segmentation and access control measures should be strengthened to limit exposure of affected devices to untrusted networks, while monitoring systems should be enhanced to detect anomalous XML traffic patterns that could indicate exploitation attempts. The vulnerability's classification as a remote code execution flaw places it in the highest risk category according to industry security frameworks, requiring immediate attention from security operations teams. Regular vulnerability assessments should be conducted to identify any remaining unpatched systems, and organizations should consider implementing network-based intrusion detection systems that can identify and block the specific XML packet patterns associated with this exploit. Additionally, the incident should trigger a comprehensive review of memory safety practices within the organization's security infrastructure and consideration of alternative approaches to VPN implementation that reduce the attack surface.