Query: EDR alert: possible Network Sniffing (T1040)
Matching passage: T1040 Network Sniffing. Tactics: credential access, discovery. Description: Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network. Network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection. An adversary may place a network interface into promiscuous mode to passively access data in transit over the network, or use span ports to capture a larger amount of data. Data captured via this technique may include user credentials, especially those sent over an insecure, unencrypted protocol. Techniques for name service resolution poisoning, such as [Name Resolution Poisoning and SMB Relay](https://attack.mitre.org/techniques/T1557/001), can also be used to capture credentials to websites, proxies, and internal systems by redirecting traffic to an adversary. Network sniffing may reveal configuration details, such as running services, version numbers, and other network characteristics (e.g. IP addresses, hostnames, VLAN IDs) necessary for subsequent [Lateral Movement](https://attack.mitre.org/tactics/TA0008) and/or [Stealth](https://attack.mitre.org/tactics/TA0005) activities. Adversaries may likely also utilize network sniffing during [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557) (AiTM) to passively gain additional knowledge about the environment. In cloud-based environments, adversaries may still be able to use traffic mirroring services to sniff network traffic from virtual machines. For example, AWS Traffic Mirroring, GCP Packet Mirroring, and Azure vTap allow users to define specified instances to collect traffic from and specified targets to send collected traffic to.(Citation: AWS Traffic Mirroring)(Citation: GCP Packet Mirroring)(Citation: Azure Virtual Network TAP) Often, much of this traffic will be in cleartext due to the use of TLS termination at the load balancer level to reduce the strain of encrypting and decrypting traffic.(Citation: R
Near-miss passage: T1556.006 Multi-Factor Authentication. Tactics: defense impairment, persistence, credential access. Description: Adversaries may disable or modify multi-factor authentication (MFA) mechanisms to enable persistent access to compromised accounts. Once adversaries have gained access to a network by either compromising an account lacking MFA or by employing an MFA bypass method such as [Multi-Factor Authentication Request Generation](https://attack.mitre.org/techniques/T1621), adversaries may leverage their access to modify or completely disable MFA defenses. This can be accomplished by abusing legitimate features, such as excluding users from Azure AD Conditional Access Policies, registering a new yet vulnerable/adversary-controlled MFA method, or by manually patching MFA programs and configuration files to bypass expected functionality.(Citation: Mandiant APT42)(Citation: Azure AD Conditional Access Exclusions) For example, modifying the Windows hosts file (`C:\windows\system32\drivers\etc\hosts`) to redirect MFA calls to localhost instead of an MFA server may cause the MFA process to fail. If a "fail open" policy is in place, any otherwise successful authentication attempt may be granted access without enforcing MFA. (Citation: Russians Exploit Default MFA Protocol - CISA March 2022) Depending on the scope, goals, and privileges of the adversary, MFA defenses may be disabled for individual accounts or for all accounts tied to a larger group, such as all domain accounts in a victim's network environment.(Citation: Russians Exploit Default MFA Protocol - CISA March 2022)