Adversaries may host seemingly genuine Wi-Fi access points to deceive users into connecting to malicious networks as a way of supporting follow-on behaviors such as Network Sniffing, Transmitted Data Manipulation, or Input Capture.^[1]

By using a Service Set Identifier (SSID) of a legitimate Wi-Fi network, fraudulent Wi-Fi access points may trick devices or users into connecting to malicious Wi-Fi networks.^[2],[3] Adversaries may provide a stronger signal strength or block access to Wi-Fi access points to coerce or entice victim devices into connecting to malicious networks.^[4] A Wi-Fi Pineapple – a network security auditing and penetration testing tool – may be deployed in Evil Twin attacks for ease of use and broader range. Custom certificates may be used in an attempt to intercept HTTPS traffic.

Similarly, adversaries may also listen for client devices sending probe requests for known or previously connected networks (Preferred Network Lists or PNLs). When a malicious access point receives a probe request, adversaries can respond with the same SSID to imitate the trusted, known network.^[4] Victim devices are led to believe the responding access point is from their PNL and initiate a connection to the fraudulent network.

Upon logging into the malicious Wi-Fi access point, a user may be directed to a fake login page or captive portal webpage to capture the victim’s credentials. Once a user is logged into the fraudulent Wi-Fi network, the adversary may able to monitor network activity, manipulate data, or steal additional credentials. Locations with high concentrations of public Wi-Fi access, such as airports, coffee shops, or libraries, may be targets for adversaries to set up illegitimate Wi-Fi access points.

References

1. Toulas, Bill. (2024, July 1). Australian charged for ‘Evil Twin’ WiFi attack on plane. Retrieved September 17, 2024.
2. AO Kaspersky Lab. (n.d.). Evil twin attacks and how to prevent them. Retrieved September 17, 2024.
3. Gihan, Kavishka. (2021, August 8). Wireless Security— Evil Twin Attack. Retrieved September 17, 2024.
4. Ryan, Gabriel. (2019, October 28). Modern Wireless Tradecraft Pt I — Basic Rogue AP Theory — Evil Twin and Karma Attacks. Retrieved September 17, 2024.

Adversaries may redirect network traffic to adversary-owned systems by spoofing Dynamic Host Configuration Protocol (DHCP) traffic and acting as a malicious DHCP server on the victim network. By achieving the adversary-in-the-middle (AiTM) position, adversaries may collect network communications, including passed credentials, especially those sent over insecure, unencrypted protocols. This may also enable follow-on behaviors such as Network Sniffing or Transmitted Data Manipulation.

DHCP is based on a client-server model and has two functionalities: a protocol for providing network configuration settings from a DHCP server to a client and a mechanism for allocating network addresses to clients.^[1] The typical server-client interaction is as follows:

1. The client broadcasts a DISCOVER message.

1. The server responds with an OFFER message, which includes an available network address.

1. The client broadcasts a REQUEST message, which includes the network address offered.

1. The server acknowledges with an ACK message and the client receives the network configuration parameters.

Adversaries may spoof as a rogue DHCP server on the victim network, from which legitimate hosts may receive malicious network configurations. For example, malware can act as a DHCP server and provide adversary-owned DNS servers to the victimized computers.^[2],[3] Through the malicious network configurations, an adversary may achieve the AiTM position, route client traffic through adversary-controlled systems, and collect information from the client network.

DHCPv6 clients can receive network configuration information without being assigned an IP address by sending a INFORMATION-REQUEST (code 11) message to the All_DHCP_Relay_Agents_and_Servers multicast address.^[4] Adversaries may use their rogue DHCP server to respond to this request message with malicious network configurations.

Rather than establishing an AiTM position, adversaries may also abuse DHCP spoofing to perform a DHCP exhaustion attack (i.e, Service Exhaustion Flood) by generating many broadcast DISCOVER messages to exhaust a network’s DHCP allocation pool.

References

1. Droms, R. (1997, March). Dynamic Host Configuration Protocol. Retrieved March 9, 2022.
2. Irwin, Ullrich, J. (2009, March 16). new rogue-DHCP server malware. Retrieved January 14, 2022.
3. Symantec. (2009, March 22). W32.Tidserv.G. Retrieved January 14, 2022.
4. J. Bound, et al. (2003, July). Dynamic Host Configuration Protocol for IPv6 (DHCPv6). Retrieved June 27, 2022.

By responding to LLMNR/NBT-NS/mDNS network traffic, adversaries may spoof an authoritative source for name resolution to force communication with an adversary controlled system.^[1] This activity may be used to collect or relay authentication materials.

Link-Local Multicast Name Resolution (LLMNR) and NetBIOS Name Service (NBT-NS) are Microsoft Windows components that serve as alternate methods of host identification. LLMNR is based upon the Domain Name System (DNS) format and allows hosts on the same local link to perform name resolution for other hosts. NBT-NS identifies systems on a local network by their NetBIOS name.^[2],[3]

Multicast Domain Name System(mDNS) is a zero-configuration service used to resolve hostnames to IP addresses with “.local” as a top-level domain. MDNS is based upon Domain Name System (DNS) format and allows hosts on the same network segment to perform name resolution for other hosts, using multicast.^[4]

Adversaries can spoof an authoritative source for name resolution on a victim network by responding to LLMNR (UDP 5355)/NBT-NS (UDP 137)/mDNS (UDP 5353) traffic as if they know the identity of the requested host, effectively poisoning the service so that the victims will communicate with the adversary controlled system. If the requested host belongs to a resource that requires identification/authentication, the username and NTLMv2 hash will then be sent to the adversary controlled system. The adversary can then collect the hash information sent over the wire through tools that monitor the ports for traffic or through Network Sniffing and crack the hashes offline through Brute Force to obtain the plaintext passwords.

In some cases where an adversary has access to a system that is in the authentication path between systems or when automated scans that use credentials attempt to authenticate to an adversary controlled system, the NTLMv1/v2 hashes can be intercepted and relayed to access and execute code against a target system. The relay step can happen in conjunction with poisoning but may also be independent of it.^[5],[6] Additionally, adversaries may encapsulate the NTLMv1/v2 hashes into various other protocols, such as LDAP, MSSQL and HTTP, to expand and use multiple services with the valid NTLM response.

Several tools may be used to poison name services within local networks such as NBNSpoof, Metasploit, and Responder.^[7],[8],[9]

References

1. Lucas Silva, Leandro Froes. (2022, April 18). An Investigation of the BlackCat Ransomware via Trend Micro Vision One. Retrieved February 2, 2026.
2. Wikipedia. (2016, July 7). Link-Local Multicast Name Resolution. Retrieved November 17, 2017.
3. Microsoft. (n.d.). NetBIOS Name Resolution. Retrieved November 17, 2017.
4. S. Cheshire, M. Krochmal. (2013, February). Multicast DNS. Retrieved February 2, 2026.
5. Salvati, M. (2017, June 2). Practical guide to NTLM Relaying in 2017 (A.K.A getting a foothold in under 5 minutes). Retrieved February 7, 2019.
6. Kuehn, E. (2018, April 11). Ever Run a Relay? Why SMB Relays Should Be On Your Mind. Retrieved February 7, 2019.
7. Nomex. (2014, February 7). NBNSpoof. Retrieved November 17, 2017.
8. Francois, R. (n.d.). LLMNR Spoofer. Retrieved November 17, 2017.
9. Gaffie, L. (2016, August 25). Responder. Retrieved November 17, 2017.

Adversaries may poison Address Resolution Protocol (ARP) caches to position themselves between the communication of two or more networked devices. This activity may be used to enable follow-on behaviors such as Network Sniffing or Transmitted Data Manipulation.

The ARP protocol is used to resolve IPv4 addresses to link layer addresses, such as a media access control (MAC) address.^[1] Devices in a local network segment communicate with each other by using link layer addresses. If a networked device does not have the link layer address of a particular networked device, it may send out a broadcast ARP request to the local network to translate the IP address to a MAC address. The device with the associated IP address directly replies with its MAC address. The networked device that made the ARP request will then use as well as store that information in its ARP cache.

An adversary may passively wait for an ARP request to poison the ARP cache of the requesting device. The adversary may reply with their MAC address, thus deceiving the victim by making them believe that they are communicating with the intended networked device. For the adversary to poison the ARP cache, their reply must be faster than the one made by the legitimate IP address owner. Adversaries may also send a gratuitous ARP reply that maliciously announces the ownership of a particular IP address to all the devices in the local network segment.

The ARP protocol is stateless and does not require authentication. Therefore, devices may wrongly add or update the MAC address of the IP address in their ARP cache.^[2],[3]

Adversaries may use ARP cache poisoning as a means to intercept network traffic. This activity may be used to collect and/or relay data such as credentials, especially those sent over an insecure, unencrypted protocol.^[2]

References

1. Plummer, D. (1982, November). An Ethernet Address Resolution Protocol. Retrieved October 15, 2020.
2. Siles, R. (2003, August). Real World ARP Spoofing. Retrieved October 15, 2020.
3. Cylance. (2014, December). Operation Cleaver. Retrieved September 14, 2017.