Adversaries may abuse netbooting to load an unauthorized network device operating system from a Trivial File Transfer Protocol (TFTP) server. TFTP boot (netbooting) is commonly used by network administrators to load configuration-controlled network device images from a centralized management server. Netbooting is one option in the boot sequence and can be used to centralize, manage, and control device images.
Adversaries may manipulate the configuration on the network device specifying use of a malicious TFTP server, which may be used in conjunction with Modify System Image to load a modified image on device startup or reset. The unauthorized image allows adversaries to modify device configuration, add malicious capabilities to the device, and introduce backdoors to maintain control of the network device while minimizing detection through use of a standard functionality. This technique is similar to ROMMONkit and may result in the network device running a modified image. (Citation: Cisco Blog Legacy Device Attacks)
View in MITRE ATT&CK®Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
---|---|---|---|---|---|
action.malware.variety.Rootkit | Rootkit (maintain local privileges and stealth) | related-to | T1542.005 | Pre-OS Boot: TFTP Boot |
Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
---|---|---|---|---|---|
amazon_virtual_private_cloud | Amazon Virtual Private Cloud | technique_scores | T1542.005 | TFTP Boot |
Comments
VPC security groups and network access control lists (NACLs) can be used to restrict clients to connecting (and therefore booting) from only trusted network resources.
References
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aws_network_firewall | AWS Network Firewall | technique_scores | T1542.005 | TFTP Boot |
Comments
AWS Network Firewall has the ability to pass, drop, or alert on traffic based on the network protocol as well as perform deep packet inspection on the payload. This functionality can be used to block traffic over known TFTP ports. This mapping is given a score of Partial because AWS Network Firewall does not do anything to protect against TFTP booting among hosts within the network and behind the firewall.
References
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