“伪造”网络适配器如何窃取凭证？含Bash Bunny类USB设备分析

Great question—let’s break down how these USB-style network attack tools pull off credential theft against HTTPS traffic, especially when dealing with automated services like Windows Update. The key here is that they rarely need to directly decrypt HTTPS (which is hard with proper certificate validation); instead, they exploit gaps in authentication protocols, system trust, or automated behavior:

• Man-in-the-Middle with Forced Certificate Trust
  Devices like Bash Bunny can mimic a local network gateway, forcing the target machine to route all traffic through them. Then, they’ll use tools like Responder or mitmproxy to generate fake SSL certificates for every HTTPS site the target connects to. The trick? These devices often double as USB HID (keyboard) emulators—they can quickly type out commands to install a malicious root CA certificate onto the Windows machine. Once that CA is trusted, Windows will accept the fake HTTPS certificates, letting the device decrypt and read all HTTPS traffic (including Windows Update authentication data).

• Credential Relay Attacks (No Decryption Needed)
  A lot of automated Windows services (including Windows Update) use NTLM or Kerberos for authentication. Instead of trying to crack the encrypted password hash, these devices can relay the captured hash to another service (like a domain controller or file server) that accepts NTLM authentication. Since many systems don’t enforce "signing required" for NTLM, the relay works—attacker gets access without ever seeing the plaintext password. For Windows Update specifically, if the device triggers a fake Update server request, the system will automatically send its machine or user credentials, which the Bunny can capture and relay.

• Abusing Auto-Authentication Triggers
  Windows is designed to automatically authenticate to trusted services without user input. Attack tools can exploit this by spoofing a service that the target machine is configured to trust (like a local intranet Update server). When the system connects to the spoofed service, it sends its credentials automatically—no user interaction needed. The device captures these credential hashes, which can be cracked offline with tools like hashcat or used directly in pass-the-hash attacks.

• Session Hijacking & Token Theft
  Beyond network traffic, these USB tools can run local scripts (via HID emulation) to steal existing authentication tokens from the target system. For example, they might execute mimikatz to grab Kerberos tickets or NT tokens that Windows uses to authenticate to HTTPS services like Update. With these tokens, the attacker can impersonate the system or user account without needing to steal a password at all.

The bottom line: HTTPS encrypts the traffic, but it doesn’t protect against flaws in how authentication is handled before the encryption starts, or against attacks that bypass decryption entirely by abusing trust or protocol weaknesses.

内容的提问来源于stack exchange，提问作者ispiro