In computer networking, Cisco ASA 5500 Series Adaptive Security Appliances, or simply Cisco ASA, is Cisco's line of network security devices introduced in May 2005.[1] It succeeded three existing lines of Cisco products:
Cisco ASA has become one of the most widely used firewall/VPN solutions for small to medium-sized businesses. Early reviews indicated the Cisco GUI tools for managing the device were lacking.[4]
A security flaw was identified when users customized the Clientless SSLVPN option of their ASA's but was rectified in 2015.[5]
Another flaw in a WebVPN feature was fixed in 2018.[6]
In 2017 The Shadow Brokers revealed the existence of two privilege escalation exploits against the ASA called EPICBANANA[7] and EXTRABACON.[8][9] A code insertion implant called BANANAGLEE, was made persistent by JETPLOW.[10]
Features
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The 5506W-X has a WiFi point included.
Architecture
The ASA software is based on Linux. It runs a single Executable and Linkable Format program called lina. This schedules processes internally rather than using the Linux facilities.[11] In the boot sequence a boot loader called ROMMON (ROM monitor) starts, loads a Linux kernel, which then loads the lina_monitor, which then loads lina. The ROMMON also has a command line that can be used to load or select other software images and configurations. The names of firmware files includes a version indicator, -smp means it is for a symmetrical multiprocessor (and 64 bit architecture), and different parts also indicate if 3DES or AES is supported or not.[11]
The ASA software has a similar interface to the Cisco IOS software on routers. There is a command line interface (CLI) that can be used to query operate or configure the device. In config mode the configuration statements are entered. The configuration is initially in memory as a running-config but would normally be saved to flash memory.[11]
The 5512-X, 5515-X, 5525-X, 5545-X and 5555-X can have an extra interface card added.[13]
The 5585-X has options for SSP. SSP stands for security services processor.[14] These range in processing power by a factor of 10, from SSP-10 SSP-20, SSP-40 and SSP-60. The ASA 5585-X has a slot for an I/O module. This slot can be subdivided into two half width modules.[15]
On the low end models, some features are limited, and uncrippling happens with installation of a Security Plus License. This enables more VLANs, or VPN peers, and also high availability.[13] Cisco AnyConnect is an extra licensable feature which operates IPSec or SSL tunnels to clients on PCs, iPhones or iPads.[16]
Models
The 5505 introduced in 2010 was a desktop unit designed for small enterprises or branch offices. It included features to reduce the need for other equipment, such as an inbuilt switch, and power over Ethernet ports.[17]
The 5585-X is a higher powered unit for datacenters introduced in 2010.[18] It runs in 32-bit mode on an Intel architecture Atom chip.[11]
Cisco determined that most of the low end devices had too little capacity to include the features needed, such as anti-virus, or sandboxing, and so introduced a new line of next-generation firewalls called Firepower. These run in 64-bit mode.[11]
^Cisco press releaseArchived 2012-12-04 at the Wayback Machine quote: "Las Vegas (Interop) May 3, 2005 – Cisco Systems, Inc., today announced the availability of the Cisco ASA 5500 Series Adaptive Security Appliance s"