Web Protocols
Where this stands
No Sigma rule can address this — the telemetry MITRE names has no Sigma logsource behind it.
Sigma has no logsource taxonomy for mobile platforms. MITRE's telemetry here is mobile EDR and device APIs, which no Sigma rule can address.
What the technique is
Adversaries may communicate using application layer protocols associated with web protocols traffic to avoid detection/network filtering by blending in with existing traffic. Commands to remote mobile devices, and often the results of those commands, will be embedded within the protocol traffic between the mobile client and server. Web protocols such as HTTP and HTTPS are used for web traffic as well as well as notification services native to mobile messaging services such as Google Cloud Messaging (GCM) and newly, Firebase Cloud Messaging (FCM), (GCM/FCM: two-way communication) and Apple Push Notification Service (APNS; one-way server-to-device). Such notification services leverage HTTP/S via the respective API and are commonly abused on Android and iOS respectively in order blend in with routine device traffic making it difficult for enterprises to inspect.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1681
Defender observes an application establishing recurrent HTTPS or FCM-based communication sessions exhibiting structured cadence, asymmetric request/response sizes, or persistent low-volume polling inconsistent with declared application functionality, potentially embedding command data within web protocol traffic.
- AN1682
Defender observes an application establishing recurrent HTTPS or APNS-related communications exhibiting structured cadence, abnormal session persistence, or notification-triggered network bursts inconsistent with user interaction patterns or declared application behavior.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.