On January 29, Cisco released an advisory for a critical vulnerability in their Adaptive Security Appliance (ASA) software. The critical flaw, assigned CVE-2018-0101, has a CVSS score of 10.0 and could allow for a denial-of-service attack and remote code execution. On February 5, Cisco updated the advisory indicating they’d found additional attack vectors and more affected products.

Identifying Systems Affected by Cisco ASA Critical Vulnerability (CVE-2018-0101)

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.

The Cisco Adaptive Security Appliance (ASA) software running on the remote device is affected by a remote code execution vulnerability due to an issue with allocating and freeing memory when processing a malicious XML payload. An unauthenticated, remote attacker can exploit the issue to cause a reload of the affected system or to remotely execute code.

According to its version, the Cisco Firepower Threat Defense (FTD) software installed on the remote host is affected by a vulnerability in the XML parser that can allow a remote, unauthenticated attacker to execute arbitrary code.

According to its self-reported version the Cisco Adaptive Security Appliance (ASA) software running on the remote device is affected by a denial of service vulnerability which could allow an unauthenticated, remote attacker to cause a reload of the affected system or to remotely execute code.

ID	Name	Product	Family	Severity
107004	Cisco ASA Remote Code Execution and Denial of Service Vulnerability (cisco-sa-20180129-asa1) (destructive check)	Nessus	CISCO	critical
106630	Cisco Firepower Threat Defense (FTD) Adaptive Security Appliance Remote Code Execution and Denial of Service Vulnerability (cisco-sa-20180129-asa1)	Nessus	CISCO	critical
106484	Cisco ASA Remote Code Execution and Denial of Service Vulnerability (cisco-sa-20180129-asa1)	Nessus	CISCO	critical

Detections

Analytics

CVE-2018-0101

critical

Tenable Plugins

critical

critical

critical