File Download From Browser Process Via Inline URL

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About the rule

Rule Type

Standard

Rule Description

Detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension. This can be abused to download arbitrary files or to hide from the user for example by launching the browser in a minimized state.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND PROCESSNAME endswith "\brave.exe,\chrome.exe,\msedge.exe,\opera.exe,\vivaldi.exe" AND COMMANDLINE contains "http" AND COMMANDLINE endswith ".7z,.dat,.dll,.exe,.hta,.ps1,.psm1,.txt,.vbe,.vbs,.zip" select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)