Automation · API / MCP 中文

Technique note · T1221

Template Injection

Adversaries may create or modify references in user document templates to conceal malicious code or force authentication attempts. For example, Microsoft’s Office Open XML (OOXML) specification defines an XML-based format for Office documents (.docx, xlsx, .pptx) to replace older binary formats (.doc, .xls, .ppt). OOXML files are packed together ZIP archives compromised of various XML files, referred to as parts, containing properties that collectively define how a document is rendered. Properties within parts may reference shared public resources accessed via online URLs. For example, template properties may reference a file, serving as a pre-formatted document blueprint, that is fetched when the document is loaded. Adversaries may abuse these templates to initially conceal malicious code to be executed via user documents. Template references injected into a document may enable malicious payloads to be fetched and executed when the document is loaded. These documents can be delivered via other techniques such as Phishing and/or Taint Shared Content and may evade static detections since no typical indicators (VBA macro, script, etc.) are present until after the malicious payload is fetched. Examples have been seen in the wild where template injection was used to load malicious code containing an exploit. Adversaries may also modify the <code>*\template</code> control word within an .rtf file to similarly conceal then download malicious code. This legitimate control word value is intended to be a file destination of a template file resource that is retrieved and loaded when an .rtf file is opened. However, adversaries may alter the bytes of an existing .rtf file to insert a template control word field to include a URL resource of a malicious payload. This technique may also enable Forced Authentication by injecting an SMB/HTTPS (or other credential prompting) URL and triggering an authentication attempt.

ATT&CK T1221 platforms — Status Active Version 20.1

Adversaries may create or modify references in user document templates to conceal malicious code or force authentication attempts. For example, Microsoft’s Office Open XML (OOXML) specification defines an XML-based format for Office documents (.docx, xlsx, .pptx) to replace older binary formats (.doc, .xls, .ppt). OOXML files are packed together ZIP archives compromised of various XML files, referred to as parts, containing properties that collectively define how a document is rendered.1 Properties within parts may reference shared public resources accessed via online URLs. For example, template properties may reference a file, serving as a pre-formatted document blueprint, that is fetched when the document is loaded. Adversaries may abuse these templates to initially conceal malicious code to be executed via user documents. Template references injected into a document may enable malicious payloads to be fetched and executed when the document is loaded.2 These documents can be delivered via other techniques such as Phishing and/or Taint Shared Content and may evade static detections since no typical indicators (VBA macro, script, etc.) are present until after the malicious payload is fetched.3 Examples have been seen in the wild where template injection was used to load malicious code containing an exploit.4 Adversaries may also modify the <code>*\template</code> control word within an .rtf file to similarly conceal then download malicious code. This legitimate control word value is intended to be a file destination of a template file resource that is retrieved and loaded when an .rtf file is opened. However, adversaries may alter the bytes of an existing .rtf file to insert a template control word field to include a URL resource of a malicious payload.56 This technique may also enable Forced Authentication by injecting an SMB/HTTPS (or other credential prompting) URL and triggering an authentication attempt.789

  1. Microsoft Open XML July 2017
  2. SANS Brian Wiltse Template Injection
  3. Redxorblue Remote Template Injection
  4. MalwareBytes Template Injection OCT 2017
  5. Proofpoint RTF Injection
  6. Ciberseguridad Decoding malicious RTF files
  7. Anomali Template Injection MAR 2018
  8. Talos Template Injection July 2017
  9. ryhanson phishery SEPT 2016

Groups using this technique

GroupNameCountry
grp_g0100Inception—
grp_g1054MirrorFace—
grp_g0142Confucius—
grp_g0035DragonflyRussia
grp_g0079DarkHydrus—
grp_g0081Tropic Trooper—
grp_g0047Gamaredon GroupRussia
grp_g0007APT28Russia

Claims

No public claim points at this technique yet.

Auto-ingested and not human-reviewed; confidence and validity read by citation.