Query: Outbound C2 pattern associated with Network Sniffing
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: T1003.008 /etc/passwd and /etc/shadow. Tactics: credential access. Description: Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking. Most modern Linux operating systems use a combination of <code>/etc/passwd</code> and <code>/etc/shadow</code> to store user account information, including password hashes in <code>/etc/shadow</code>. By default, <code>/etc/shadow</code> is only readable by the root user.(Citation: Linux Password and Shadow File Formats) Linux stores user information such as user ID, group ID, home directory path, and login shell in <code>/etc/passwd</code>. A "user" on the system may belong to a person or a service. All password hashes are stored in <code>/etc/shadow</code> - including entries for users with no passwords and users with locked or disabled accounts.(Citation: Linux Password and Shadow File Formats) Adversaries may attempt to read or dump the <code>/etc/passwd</code> and <code>/etc/shadow</code> files on Linux systems via command line utilities such as the <code>cat</code> command.(Citation: Arctic Wolf) Additionally, the Linux utility <code>unshadow</code> can be used to combine the two files in a format suited for password cracking utilities such as John the Ripper - for example, via the command <code>/usr/bin/unshadow /etc/passwd /etc/shadow > /tmp/crack.password.db</code>(Citation: nixCraft - John the Ripper). Since the user information stored in <code>/etc/passwd</code> are linked to the password hashes in <code>/etc/shadow</code>, an adversary would need to have access to both.