InformationalSplunk security content Michael Haag +1

Windows IIS Components Add New Module

Description

The following analytic detects the execution of AppCmd.exe to install a new module in IIS. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity is significant as adversaries may use it to install webshells or backdoors, leading to credit card scraping, persistence, and further post-exploitation. If confirmed malicious, this could allow attackers to maintain persistent access, execute arbitrary code, and potentially exfiltrate sensitive information from the compromised web server.

Detection logic

Detection requirements

Platform: Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
Log source category: crowdstrike_processrollup2 sysmon_eventid_1 windows_event_log_security_4688

Known benign triggers

False positives may be present until properly tuned. Filter as needed.

References

Links the source published beside this detection. Reference is the link the source wrote, unmodified. Class is decided by this catalogue from the host and path, not stated by the source. Cited by counts published detections citing the same resource, including this one, and the sources beneath it count the repositories this catalogue ingests, which is not the same as independent research.
Reference	Class	Cited by
github.com/redcanaryco/atomic-red-team/blob/388942adbd9641f4dfdcf079d7efe9a75ec0ac43/atomics/T1505.004/T1505.004.yaml#L5	Detection test	3
github.com/redcanaryco/atomic-red-team/tree/master/atomics/T1505.004	Detection test	5
strontic.github.io/xcyclopedia/library/appcmd.exe-055B2B09409F980BF9B5A3969D01E5B2.html	Unclassified	4
unit42.paloaltonetworks.com/unit42-oilrig-uses-rgdoor-iis-backdoor-targets-middle-east/	Threat report	6
www.crowdstrike.com/wp-content/uploads/2022/05/crowdstrike-iceapple-a-novel-internet-information-services-post-exploitation-framework-1.pdf	Security research	6
www.microsoft.com/en-us/security/blog/2022/12/12/iis-modules-the-evolution-of-web-shells-and-how-to-detect-them/	Threat report	11from 2 sources
www.secureworks.com/research/bronze-union	Unclassified	6

Detection rules

Windows IIS Components Add New Module

Description

Detection logic

Detection requirements

Known benign triggers

MITRE ATT&CK mappings

References

From the source

Licence

Authorship

Detection rules