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MITRE ATT&CK® Technique

T1505.004: IIS Components

Adversaries may install malicious components that run on Internet Information Services (IIS) web servers to establish persistence. IIS provides several mechanisms to extend the functionality of the web servers. For example, Internet Server Application Programming Interface (ISAPI) extensions and filters can be installed to examine and/or modify incoming and outgoing IIS web requests. Extensions and filters are deployed as DLL files that export three functions: Get{Extension/Filter}Version, Http{Extension/Filter}Proc, and (optionally) Terminate{Extension/Filter}. IIS modules may also be installed to extend IIS web servers.[1][2][3][4]

Adversaries may install malicious ISAPI extensions and filters to observe and/or modify traffic, execute commands on compromised machines, or proxy command and control traffic. ISAPI extensions and filters may have access to all IIS web requests and responses. For example, an adversary may abuse these mechanisms to modify HTTP responses in order to distribute malicious commands/content to previously comprised hosts.[2][1][5][6][4][7]

Adversaries may also install malicious IIS modules to observe and/or modify traffic. IIS 7.0 introduced modules that provide the same unrestricted access to HTTP requests and responses as ISAPI extensions and filters. IIS modules can be written as a DLL that exports RegisterModule, or as a .NET application that interfaces with ASP.NET APIs to access IIS HTTP requests.[8][4][9]

EnterpriseT1505.004Sub-techniqueObject v1.1Modified
Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

Malicious IIS components matter because they turn a Windows web server’s normal extension points into persistence. If an attacker can install an ISAPI extension, ISAPI filter, or IIS module, that code may observe or modify HTTP requests and responses, execute commands, or proxy command-and-control traffic through a trusted server path. For leaders, the issue is not only malware on a host; it is loss of trust in a public-facing application platform that may handle credentials, customer traffic, or business-critical services.

Executive priority

Prioritize this where IIS supports externally reachable, regulated, or mission-critical applications. The key business questions are: who can change IIS components, how quickly can the team prove what modules and DLLs are legitimate, and whether audit evidence exists to reconstruct unauthorized changes. This technique supports persistence, so incident decisions should include server rebuild or component validation planning rather than only web log review.

Technical view

For Windows IIS servers, validate the inventory and change history of ISAPI extensions, ISAPI filters, and IIS modules, including native DLL modules and .NET modules. Review whether components export or implement expected IIS functions such as GetExtensionVersion, HttpExtensionProc, GetFilterVersion, HttpFilterProc, TerminateExtension/Filter, or RegisterModule when applicable. Because ATT&CK does not provide official detection text for this object, detection engineering should anchor on configuration drift, unauthorized code execution under IIS, suspicious module/filter registration, and unusual web request/response handling patterns. Relationship context shows this is a sub-technique of Server Software Component and is associated with reported software/campaign usage, so treat it as a persistence validation item during IIS compromise investigations.

Likely telemetry

  • IIS configuration data showing registered modules, ISAPI extensions, and ISAPI filters
  • File system evidence for IIS-related DLLs and .NET module artifacts, including creation and modification times
  • Windows host audit logs covering privileged changes and administrative activity on IIS servers
  • IIS web logs and application logs for unusual request patterns or server behavior
  • Process and module-loading telemetry for IIS worker processes where available

Detection direction

  • Establish a known-good baseline of IIS modules, ISAPI filters, ISAPI extensions, paths, hashes, owners, and signing status, then alert on additions or changes.
  • Tune for authorized deployment noise by integrating change-management records; IIS extension changes can be legitimate during application releases.
  • Validate visibility into both native DLL-based modules and .NET modules, since the ATT&CK description covers both.
  • Correlate suspicious component changes with privileged account activity, web traffic anomalies, and unexpected IIS worker process behavior.
  • Use the related DET0068 detection strategy as a pointer for coverage planning, but confirm local details because the supplied ATT&CK object contains no official detection procedure text.

Mitigation priorities

  • Restrict who can administer IIS and modify server components using privileged account management and least privilege.
  • Apply execution prevention so only authorized code can run on IIS servers where feasible.
  • Require and verify trusted code-signing for IIS-related binaries and deployment artifacts, recognizing that signing should be one control among several.
  • Maintain regular auditing of IIS configuration, component inventory, privileged changes, and server-side file integrity.
  • Include IIS component review in incident response playbooks for Windows web server compromise and persistence eradication.
Additional notes and limits

The object is a Windows persistence sub-technique under Server Software Component. ATT&CK relationships list detections and mitigations, plus use by campaigns and software such as OwaAuth, RGDoor, and IceApple; these relationships show the behavior is documented in ATT&CK, not that any specific environment is affected. The most useful defensive outcome is the ability to quickly distinguish legitimate IIS extensibility from unauthorized persistence.

The official ATT&CK detection field for this object is not provided. Telemetry and control guidance therefore must be validated against the organization’s IIS versions, deployment model, logging configuration, and change-management process. No claim is made here about active exploitation, attribution, or guaranteed detection coverage.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

IIS Components

Adversaries may install malicious components that run on Internet Information Services (IIS) web servers to establish persistence. IIS provides several mechanisms to extend the functionality of the web servers. For example, Internet Server Application Programming Interface (ISAPI) extensions and filters can be installed to examine and/or modify incoming and outgoing IIS web requests. Extensions and filters are deployed as DLL files that export three functions: Get{Extension/Filter}Version, Http{Extension/Filter}Proc, and (optionally) Terminate{Extension/Filter}. IIS modules may also be installed to extend IIS web servers.[1][2][3][4]

Adversaries may install malicious ISAPI extensions and filters to observe and/or modify traffic, execute commands on compromised machines, or proxy command and control traffic. ISAPI extensions and filters may have access to all IIS web requests and responses. For example, an adversary may abuse these mechanisms to modify HTTP responses in order to distribute malicious commands/content to previously comprised hosts.[2][1][5][6][4][7]

Adversaries may also install malicious IIS modules to observe and/or modify traffic. IIS 7.0 introduced modules that provide the same unrestricted access to HTTP requests and responses as ISAPI extensions and filters. IIS modules can be written as a DLL that exports RegisterModule, or as a .NET application that interfaces with ASP.NET APIs to access IIS HTTP requests.[8][4][9]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Related techniques

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

1 rows
DomainIDNameRelationship / procedure
EnterpriseT1505Server Software ComponentThis object subtechnique of Server Software Component.
Associated objects

Groups, software, and campaigns

MalwareEnterprise

S0258: RGDoor

RGDoor is a malicious Internet Information Services (IIS) backdoor developed in the C++ language. RGDoor has been seen deployed on webservers belonging to the Middle East government organizations. RGDoor provides backdoor access to compromised IIS servers. [1]

Windows
MalwareEnterprise

S1022: IceApple

IceApple is a modular Internet Information Services (IIS) post-exploitation framework, that has been used since at least 2021 against the technology, academic, and government sectors.[1]

Windows
CampaignEnterprise

C0022: Operation Dream Job

Operation Dream Job was a cyber espionage operation likely conducted by Lazarus Group that targeted the defense, aerospace, government, and other sectors in the United States, Israel, Australia, Russia, and India. In at least one case, the cyber actors tried to monetize their network access to conduct a business email compromise (BEC) operation. In 2020, security researchers noted overlapping TTPs, to include fake job lures and code similarities, between Operation Dream Job, Operation North Star, and Operation Interception; by 2022 security researchers described Operation Dream Job as an umbrella term covering both Operation Interception and Operation North Star.[1][2][3][4]

CampaignEnterprise

C0058: SharePoint ToolShell Exploitation

The SharePoint ToolShell Exploitation campaign was conducted in July 2025 and encompassed the first waves of exploitation against incompletely patched spoofing (CVE-2025-49706) and remote code execution (CVE-2025-49704) vulnerabilities affecting on-premises Microsoft SharePoint servers. Later patched and updated as CVE-2025-53770 and CVE-2025-53771, the ToolShell vulnerabilities were widely exploited including by China-based ransomware actor Storm-2603 and espionage actors Threat Group-3390 and ZIRCONIUM. SharePoint ToolShell Exploitation targeted multiple regions and industries including finance, education, energy, and healthcare across Asia, Europe, and the United States.[1][2][3][4][5]

Relationship explorer

All related ATT&CK context

Mitigations

Mitigation direction

Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.

ATT&CK release
19.1
Object version
1.1
Created
Modified
Raw hash
0d59af3172cd8fd7...
Imported snapshots across ATT&CK releases(1)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.11.1Current bundle0d59af3172cd…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    Microsoft ISAPI Extension Overview 2017

    Microsoft. (2017, June 16). ISAPI Extension Overview. Retrieved June 3, 2021.

    Open source URL
  2. [2]
    Microsoft ISAPI Filter Overview 2017

    Microsoft. (2017, June 16). ISAPI Filter Overview. Retrieved June 3, 2021.

    Open source URL
  3. [3]
    IIS Backdoor 2011

    Julien. (2011, February 2). IIS Backdoor. Retrieved June 3, 2021.

    Open source URL
  4. [4]
    Trustwave IIS Module 2013

    Grunzweig, J. (2013, December 9). The Curious Case of the Malicious IIS Module. Retrieved June 3, 2021.

    Open source URL
  5. [5]
    Microsoft ISAPI Extension All Incoming 2017

    Microsoft. (2017, June 16). Intercepting All Incoming IIS Requests. Retrieved June 3, 2021.

    Open source URL
  6. [6]
    Dell TG-3390

    Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.

    Open source URL
  7. [7]
    MMPC ISAPI Filter 2012

    MMPC. (2012, October 3). Malware signed with the Adobe code signing certificate. Retrieved June 3, 2021.

    Open source URL
  8. [8]
    Microsoft IIS Modules Overview 2007

    Microsoft. (2007, November 24). IIS Modules Overview. Retrieved June 17, 2021.

    Open source URL
  9. [9]
    ESET IIS Malware 2021

    Hromcová, Z., Cherepanov, A. (2021). Anatomy of Native IIS Malware. Retrieved September 9, 2021.

    Open source URL
  10. [10]
    Unit 42 RGDoor Jan 2018

    Falcone, R. (2018, January 25). OilRig uses RGDoor IIS Backdoor on Targets in the Middle East. Retrieved July 6, 2018.

    Open source URL
  11. [11]
    CrowdStrike IceApple May 2022

    CrowdStrike. (2022, May). ICEAPPLE: A NOVEL INTERNET INFORMATION SERVICES (IIS) POST-EXPLOITATION FRAMEWORK. Retrieved June 27, 2022.

    Open source URL
  12. [12]
    Microsoft ISAPICGIRestriction 2016

    Microsoft. (2016, September 26). ISAPI/CGI Restrictions <isapiCgiRestriction>. Retrieved June 3, 2021.

    Open source URL
  13. [13]
    McAfee Lazarus Jul 2020

    Cashman, M. (2020, July 29). Operation North Star Campaign. Retrieved December 20, 2021.

    Open source URL
  14. [14]
    Microsoft SharePoint Exploit JUL 2025

    Microsoft Threat Intelligence. (2025, July 22). Disrupting active exploitation of on-premises SharePoint vulnerabilities. Retrieved October 15, 2025.

    Open source URL
  15. [15]
    Dell TG-3390

    Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.

    Open source URL
  16. [16]
    Dell TG-3390

    Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.

    Open source URL
  17. [17]
    ESET IIS Malware 2021

    Hromcová, Z., Cherepanov, A. (2021). Anatomy of Native IIS Malware. Retrieved September 9, 2021.

    Open source URL
  18. [18]
    ESET IIS Malware 2021

    Hromcová, Z., Cherepanov, A. (2021). Anatomy of Native IIS Malware. Retrieved September 9, 2021.

    Open source URL
  19. [19]
    IIS Backdoor 2011

    Julien. (2011, February 2). IIS Backdoor. Retrieved June 3, 2021.

    Open source URL
  20. [20]
    IIS Backdoor 2011

    Julien. (2011, February 2). IIS Backdoor. Retrieved June 3, 2021.

    Open source URL
  21. [21]
    MMPC ISAPI Filter 2012

    MMPC. (2012, October 3). Malware signed with the Adobe code signing certificate. Retrieved June 3, 2021.

    Open source URL
  22. [22]
    MMPC ISAPI Filter 2012

    MMPC. (2012, October 3). Malware signed with the Adobe code signing certificate. Retrieved June 3, 2021.

    Open source URL
  23. [23]
    Microsoft IIS Modules Overview 2007

    Microsoft. (2007, November 24). IIS Modules Overview. Retrieved June 17, 2021.

    Open source URL
  24. [24]
    Microsoft IIS Modules Overview 2007

    Microsoft. (2007, November 24). IIS Modules Overview. Retrieved June 17, 2021.

    Open source URL
  25. [25]
    Microsoft ISAPI Extension All Incoming 2017

    Microsoft. (2017, June 16). Intercepting All Incoming IIS Requests. Retrieved June 3, 2021.

    Open source URL
  26. [26]
    Microsoft ISAPI Extension All Incoming 2017

    Microsoft. (2017, June 16). Intercepting All Incoming IIS Requests. Retrieved June 3, 2021.

    Open source URL
  27. [27]
    Microsoft ISAPI Extension Overview 2017

    Microsoft. (2017, June 16). ISAPI Extension Overview. Retrieved June 3, 2021.

    Open source URL
  28. [28]
    Microsoft ISAPI Extension Overview 2017

    Microsoft. (2017, June 16). ISAPI Extension Overview. Retrieved June 3, 2021.

    Open source URL
  29. [29]
    Microsoft ISAPI Filter Overview 2017

    Microsoft. (2017, June 16). ISAPI Filter Overview. Retrieved June 3, 2021.

    Open source URL
  30. [30]
    Microsoft ISAPI Filter Overview 2017

    Microsoft. (2017, June 16). ISAPI Filter Overview. Retrieved June 3, 2021.

    Open source URL
  31. [31]
    Trustwave IIS Module 2013

    Grunzweig, J. (2013, December 9). The Curious Case of the Malicious IIS Module. Retrieved June 3, 2021.

    Open source URL
  32. [32]
    Trustwave IIS Module 2013

    Grunzweig, J. (2013, December 9). The Curious Case of the Malicious IIS Module. Retrieved June 3, 2021.

    Open source URL
  33. [33]
    Unit 42 RGDoor Jan 2018

    Falcone, R. (2018, January 25). OilRig uses RGDoor IIS Backdoor on Targets in the Middle East. Retrieved July 6, 2018.

    Open source URL
  34. [34]
    Unit 42 RGDoor Jan 2018

    Falcone, R. (2018, January 25). OilRig uses RGDoor IIS Backdoor on Targets in the Middle East. Retrieved July 6, 2018.

    Open source URL
  35. [35]
    mitre-attackT1505.004
    Open source URL
  36. [36]
    mitre-attackT1505.004
    Open source URL
  37. [37]
    mitre-attackT1505.004
    Open source URL
  38. [38]
    ESET IIS Malware 2021

    Hromcová, Z., Cherepanov, A. (2021). Anatomy of Native IIS Malware. Retrieved September 9, 2021.

    Open source URL
  39. [39]
    ESET IIS Malware 2021

    Hromcová, Z., Cherepanov, A. (2021). Anatomy of Native IIS Malware. Retrieved September 9, 2021.

    Open source URL
  40. [40]
    Unit 42 RGDoor Jan 2018

    Falcone, R. (2018, January 25). OilRig uses RGDoor IIS Backdoor on Targets in the Middle East. Retrieved July 6, 2018.

    Open source URL
  41. [41]
    Unit 42 RGDoor Jan 2018

    Falcone, R. (2018, January 25). OilRig uses RGDoor IIS Backdoor on Targets in the Middle East. Retrieved July 6, 2018.

    Open source URL
  42. [42]
    CrowdStrike IceApple May 2022

    CrowdStrike. (2022, May). ICEAPPLE: A NOVEL INTERNET INFORMATION SERVICES (IIS) POST-EXPLOITATION FRAMEWORK. Retrieved June 27, 2022.

    Open source URL
  43. [43]
    Microsoft ISAPICGIRestriction 2016

    Microsoft. (2016, September 26). ISAPI/CGI Restrictions <isapiCgiRestriction>. Retrieved June 3, 2021.

    Open source URL
  44. [44]
    McAfee Lazarus Jul 2020

    Cashman, M. (2020, July 29). Operation North Star Campaign. Retrieved December 20, 2021.

    Open source URL
  45. [45]
    Microsoft SharePoint Exploit JUL 2025

    Microsoft Threat Intelligence. (2025, July 22). Disrupting active exploitation of on-premises SharePoint vulnerabilities. Retrieved October 15, 2025.

    Open source URL
  46. [46]
    Dell TG-3390

    Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.

    Open source URL
  47. [47]
    Dell TG-3390

    Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.

    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.