Adversary-in-the-Middle

Adversaries may attempt to position themselves between two or more networked devices to support follow-on behaviors such as Transmitted Data Manipulation or Endpoint Denial of Service.

Adversary-in-the-Middle can be achieved through several mechanisms, such as a malicious application registering itself as a VPN client. By doing this, the adversary can effectively redirect device traffic to wherever they want. However, registering as a VPN client requires user consent on both Android and iOS. Additionally, on iOS, the application requires a special entitlement that must be granted by Apple. Alternatively, if an application is able to escalate privileges, it can potentially utilize those privileges to gain access to network traffic.

Outside of a mobile device, adversaries may be able to capture traffic by employing a rogue base station or Wi-Fi access point. These devices will allow adversaries to capture network traffic after it has left the device, while it is flowing to its destination. On a local network, enterprise techniques could be used, such as DNS redirection or DNS poisoning.

If applications properly encrypt their network traffic, sensitive data may not be accessible an adversary, depending on the point of capture.

ID: T1638
Sub-techniques:  No sub-techniques
Tactic Type: Post-Adversary Device Access
Tactic: Collection
Platforms: Android, iOS
Version: 2.0
Created: 05 April 2022
Last Modified: 11 April 2022

Procedure Examples

ID Name Description
S0288 KeyRaider

Most KeyRaider samples hook SSLRead and SSLWrite functions in the itunesstored process to intercept device communication with the Apple App Store.[1]

S0407 Monokle

Monokle can install attacker-specified certificates to the device's trusted certificate store, enabling an adversary to perform adversary-in-the-middle attacks.[2]

Mitigations

ID Mitigation Description
M1009 Encrypt Network Traffic

Applications that properly encrypt network traffic may evade some forms of AiTM behavior.

M1006 Use Recent OS Version

Recent OS versions have made it more difficult for applications to register as VPN providers.

Detection

Application vetting services should look for applications that request VPN access. These applications should be heavily scrutinized since VPN functionality is not very common. Mobile security products can potentially detect rogue Wi-Fi access points if the adversary is attempting to decrypt traffic using an untrusted SSL certificate.

On both Android and iOS, users must grant consent to an application to act as a VPN. Both platforms also provide visual context to the user in the top status bar when a VPN connection is active. Users can see registered VPN services in the device settings.

References