Adversaries may transfer tools or other files from an external system onto a compromised device to facilitate follow-on actions. Files may be copied from an external adversary-controlled system through the command and control channel or through alternate protocols with another tool such as FTP.
RedDrop uses ads or other links within websites to encourage users to download the malicious apps using a complex content distribution network (CDN) and series of network redirects. RedDrop also downloads additional components (APKs, JAR files) from different C2 servers.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Application vetting services could look for connections to unknown domains or IP addresses. Application vetting services may indicate precisely what content was requested during application execution.