Cisco informed customers on Monday that updates released for its Adaptive Security Appliance (ASA) software patch a critical vulnerability that can be exploited to gain full control of devices or cause them to reload.
The security hole, tracked as CVE-2018-0101 and assigned a CVSS score of 10, allows a remote and unauthenticated attacker to execute arbitrary code or cause a denial-of-service (DoS) condition.
The flaw exists in the Secure Sockets Layer (SSL) VPN functionality of the ASA software. If this “webvpn” feature is enabled on a device, an attempt to double free a memory region occurs. A remote attacker can trigger the bug by sending specially crafted XML packets to a webvpn-configured interface.
Several security appliances using ASA software are affected, including 3000 Series Industrial Security Appliances (ISA), ASA 5500 security appliances and firewalls, ASA services modules for Catalyst 6500 series switches and 7600 series routers, ASA cloud firewalls, ASAv virtual appliances, and various Firepower devices.
Cisco has released fixes for each of the affected ASA releases, except for ones that are no longer supported.
Cisco is not aware of any malicious attacks exploiting this flaw, but its product security incident response team (PSIRT) “is aware of public knowledge of the vulnerability.”
Researchers at NCC Group have been investigating Cisco ASA devices and their firmware, and they have released a series of tools and blog posts dedicated to analyzing ASA firmware and finding vulnerabilities.
The experts started analyzing Cisco’s ASA software following the discovery of two critical vulnerabilities back in 2016, namely the IKEv1/IKEv2 buffer overflow tracked as CVE-2016-1287, and CVE-2016-6366, which Cisco identified following the release of an Equation Group exploit by the Shadow Brokers hacker group.