The following analytic identifies suspicious DLL modules loaded by calc.exe that are not in windows %systemroot%\system32 or %systemroot%\sysWoW64 folder. This technique is well used by Qakbot malware to execute its malicious DLL file via dll side loading technique in calc process execution. This TTP detection is a good indicator that a suspicious dll was loaded in a public or non-common installation folder of Windows Operating System that needs further investigation.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-10-24
- Author: Teoderick Contreras, Splunk
- ID: af01f6db-26ac-440e-8d89-2793e303f137
Kill Chain Phase
- CIS 10
1 2 3 4 5 `sysmon` EventCode=7 Image = "*\calc.exe" AND NOT (Image IN ("*:\\windows\\system32\\*", "*:\\windows\\sysWow64\\*")) AND NOT(ImageLoaded IN("*:\\windows\\system32\\*", "*:\\windows\\sysWow64\\*", "*:\\windows\\WinSXS\\*")) | stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded OriginalFileName Product process_name Computer EventCode Signed ProcessId | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_dll_side_loading_in_calc_filter`
The SPL above uses the following Macros:
windows_dll_side-loading_in_calc_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search you need to be ingesting information on processes that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Filesystem node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
Associated Analytic Story
|90.0||90||100||a dll modules is loaded by calc.exe in $ImageLoaded$ that are not in common windows OS installation folder in $Computer$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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