Name:Windows DLL Side-Loading In Calc id:af01f6db-26ac-440e-8d89-2793e303f137 version:11 date:2026-03-10 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects the loading of the "WindowsCodecs.dll" by calc.exe from a non-standard location This could be indicative of a potential DLL side-loading technique. This detection leverages Sysmon EventCode 7 to identify the DLL side-loading activity. In previous versions of the "calc.exe" binary, namely on Windows 7, it was vulnerable to DLL side-loading, where an attacker is able to load an arbitrary DLL named "WindowsCodecs.dll". This technique has been observed in Qakbot malware. This activity is significant as it indicates potential malware execution through a trusted process, which can bypass security controls. If confirmed malicious, this could allow attackers to execute arbitrary code, maintain persistence, and escalate privileges within the environment. Data_source:
-Sysmon EventID 7
search:'`sysmon` EventCode=7 Image="*\\calc.exe" ImageLoaded="*\\WindowsCodecs.dll" NOT Image IN ("*:\\Windows\\System32\\*", "*:\\Windows\\SysWOW64\\*") NOT ImageLoaded IN("*:\\Windows\\System32\\*", "*:\\Windows\\SysWOW64\\*", "*:\\Windows\\WinSXS\\*")
| fillnull | stats count min(_time) as firstTime max(_time) as lastTime
by Image ImageLoaded dest loaded_file loaded_file_path original_file_name process_exec process_guid process_hash process_id process_name process_path service_dll_signature_exists service_dll_signature_verified signature signature_id user_id vendor_product
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 `Processes` and `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:No false positives have been identified at this time. References: -https://www.bitdefender.com/blog/hotforsecurity/new-qakbot-malware-strain-replaces-windows-calculator-dll-to-infected-pcs/ -https://www.menlosecurity.com/blog/an-anatomy-of-heat-attacks-used-by-qakbot-campaigns drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Qakbot' - 'Earth Alux' asset_type:Endpoint mitre_attack_id: - 'T1574.001' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
