Intelligent CISO Issue 14 | Page 68

decrypting myths Evil twin APs will mimic legitimate APs, spoofing SSIDs and usually MAC addresses as well. impossible to keep an eye on everyone there. It’s feasible for someone to jump into the wire closet and plug in the cheapest AP they could get. Now they can gain access to the company’s private secure network and hijack POS systems to reveal credit card numbers or access building controls like door locks, alarms and cameras. Wi-Fi systems need to detect if a signal in the air is being broadcast from an AP physically connected to the authorised network. If so, it needs to be able to prevent the Rogue AP from gaining access to the LAN, which is typically done via ARP poisoning. It should also be able to prevent Wi-Fi clients from associating to it, usually via a surgical flood of de-authentication frames. 2. Evil twin APs Evil twin APs will mimic legitimate APs, spoofing SSIDs and usually MAC addresses as well. Attackers can then intercept traffic as the man-in-the- middle (MitM). How exactly does this work? Once a victim is connected, the attacker can steal credentials, inject malicious code into the victim’s browsers, redirect the victim to a malware site and so much more. A Wi-Fi security system must not interfere with clients not administered by the authorised network, but at the same time must detect when evil twin APs are attempting to get authorised clients connected to them and prevent this association with de-authentication floods and other techniques. 68 3. Neighbour APs This threat occurs when an authorised, company-managed client connects to a guest or external access point, bypassing the company’s perimeter security and getting around security restrictions set by the firewall. There’s actually no super-secret hacker trick to this one. Any employee could be (and probably is) doing this right now. Wi-Fi solutions must be able to automatically classify client devices managed by the company as authorised clients and prevent them from connecting to any other SSID than the ones IT administrators have defined. Prevention techniques for this threat again include surgical de-authentication floods. 4. Rogue clients Any client previously connected to a rogue AP or other malicious AP within the range of a private network is considered a rogue client. A client that connected to a rogue AP could have Issue 14 | www.intelligentciso.com