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 LLMNR/NBT-NS Poisoning and SMB Relay, 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 and/or Defense Evasion activities. Adversaries may likely also utilize network sniffing during Adversary-in-the-Middle (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: Rhino Security Labs AWS VPC Traffic Mirroring)(Citation: SpecterOps AWS Traffic Mirroring) The adversary can then use exfiltration techniques such as Transfer Data to Cloud Account in order to access the sniffed traffic.(Citation: Rhino Security Labs AWS VPC Traffic Mirroring)
On network devices, adversaries may perform network captures using Network Device CLI commands such as monitor capture.(Citation: US-CERT-TA18-106A)(Citation: capture_embedded_packet_on_software)
| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| CVE-2022-1040 | Sophos Firewall Authentication Bypass Vulnerability | secondary_impact | T1040 | Network Sniffing |
Comments
This authentication bypass vulnerability is exploited by remote attackers via the User Portal and Webadmin components. This vulnerability allows an attacker to execute arbitrary code on the victim machine.
It was actively exploited by Chinese state-sponsored APT groups, including "Drifting Cloud," to target organizations and governments across South Asia, particularly in Afghanistan, Bhutan, India, Nepal, Pakistan, and Sri Lanka. The attackers leveraged this vulnerability to deploy webshells, conduct man-in-the-middle attacks by modifying DNS responses, and intercept user credentials and session cookies from content management systems.
This vulnerability was exploited by Chinese state-sponsored threat actors as part of a broader campaign named "Pacific Rim." This campaign involved multiple Chinese APT groups, including APT31, APT41, and Volt Typhoon, targeting Sophos firewalls. The backdoor PygmyGoat, a novel rootkit that takes the form of a shared object ("libsophos.so"), has been found to be delivered following the exploitation of this vulnerability. The use of the rootkit was observed between March and April 2022 on a government device and a technology partner, and again in May 2022 on a machine in a military hospital based in Asia.
This vulnerability was also exploited by at least two advanced persistent threat (APT) groups in a highly targeted attack campaign. The attackers used the vulnerability to place malicious files into a fixed filesystem location on affected devices, leveraging a combination of authentication bypass and command injection to execute arbitrary commands as root.
The attack involved deploying various malware families, including GoMet and Gh0st RAT, to maintain persistent access and exfiltrate sensitive data. The attackers demonstrated significant knowledge of the device firmware, using custom ELF binaries and runtime packers like VMProtect to complicate analysis. They manipulated internal commands to move and manipulate files, execute processes, and exfiltrate data. The campaign targeted network security devices, employing a two-stage attack to drop remote access tools and execute commands remotely.
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