Emerging Threathightest

IcedID Malware Suspicious Single Digit DLL Execution Via Rundll32

Detects RunDLL32.exe executing a single digit DLL named "1.dll" with the export function "DllRegisterServer". This behaviour was often seen used by malware and especially IcedID

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Launch

Nasreddine Bencherchali (Nextron Systems)Created Thu Aug 312bd8e100-5b3b-4b6a-bbb5-b129d3ddddc52023

Emerging Threat

Active Threat

Developed to detect an active or emerging threat. Prioritize investigation of any alerts and correlate with threat intelligence.

Log Source

WindowsProcess Creation

ProductWindows← raw: windows

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

detection:
    selection:
        Image|endswith: '\rundll32.exe'
        CommandLine|endswith:
            - '\1.dll, DllRegisterServer' # In case of full path exec
            - ' 1.dll, DllRegisterServer' # In case of direct exec
    condition: selection